Création des Logiciels de gestion d'Entreprise, Création et référencement des sites web, Réseaux et Maintenance, Conception
salam every one, this is a topic from google web master centrale blog:
Recently, Danny Sullivan brought up good questions about how search engines handle meta tags. Here are some answers about how we handle these tags at Google.
Multiple content values
We recommend that you place all content values in one meta tag. This keeps the meta tags easy to read and reduces the chance for conflicts. For instance:
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
If the page contains multiple meta tags of the same type, we will aggregate the content values. For instance, we will interpret
<META NAME="ROBOTS" CONTENT="NOINDEX">
<META NAME="ROBOTS" CONTENT="NOFOLLOW">
The same way as:
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
If content values conflict, we will use the most restrictive. So, if the page has these meta tags:
<META NAME="ROBOTS" CONTENT="NOINDEX">
<META NAME="ROBOTS" CONTENT="INDEX">
We will obey the NOINDEX value.
Unnecessary content values
By default, Googlebot will index a page and follow links to it. So there's no need to tag pages with content values of INDEX or FOLLOW.
Directing a robots meta tag specifically at Googlebot
To provide instruction for all search engines, set the meta name to "ROBOTS". To provide instruction for only Googlebot, set the meta name to "GOOGLEBOT". If you want to provide different instructions for different search engines (for instance, if you want one search engine to index a page, but not another), it's best to use a specific meta tag for each search engine rather than use a generic robots meta tag combined with a specific one. You can find a list of bots at robotstxt.org.
Casing and spacing
Googlebot understands any combination of lowercase and uppercase. So each of these meta tags is interpreted in exactly the same way:
<meta name="ROBOTS" content="NOODP">
<meta name="robots" content="noodp">
<meta name="Robots" content="NoOdp">
If you have multiple content values, you must place a comma between them, but it doesn't matter if you also include spaces. So the following meta tags are interpreted the same way:
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
<META NAME="ROBOTS" CONTENT="NOINDEX,NOFOLLOW">
If you use both a robots.txt file and robots meta tags
If the robots.txt and meta tag instructions for a page conflict, Googlebot follows the most restrictive. More specifically:
Googlebot interprets the following robots meta tag values:
As defined by robotstxt.org, the following direction means NOINDEX, NOFOLLOW.
<META NAME="ROBOTS" CONTENT="NONE">
However, some webmasters use this tag to indicate no robots restrictions and inadvertently block all search engines from their content.
Update: For more information, please see our robots meta tag documentation.
this is a topic published in 2013... to get contents for your blog or your forum, just contact me at: devnasser@gmail.comMultiple content values
We recommend that you place all content values in one meta tag. This keeps the meta tags easy to read and reduces the chance for conflicts. For instance:
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
If the page contains multiple meta tags of the same type, we will aggregate the content values. For instance, we will interpret
<META NAME="ROBOTS" CONTENT="NOINDEX">
<META NAME="ROBOTS" CONTENT="NOFOLLOW">
The same way as:
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
If content values conflict, we will use the most restrictive. So, if the page has these meta tags:
<META NAME="ROBOTS" CONTENT="NOINDEX">
<META NAME="ROBOTS" CONTENT="INDEX">
We will obey the NOINDEX value.
Unnecessary content values
By default, Googlebot will index a page and follow links to it. So there's no need to tag pages with content values of INDEX or FOLLOW.
Directing a robots meta tag specifically at Googlebot
To provide instruction for all search engines, set the meta name to "ROBOTS". To provide instruction for only Googlebot, set the meta name to "GOOGLEBOT". If you want to provide different instructions for different search engines (for instance, if you want one search engine to index a page, but not another), it's best to use a specific meta tag for each search engine rather than use a generic robots meta tag combined with a specific one. You can find a list of bots at robotstxt.org.
Casing and spacing
Googlebot understands any combination of lowercase and uppercase. So each of these meta tags is interpreted in exactly the same way:
<meta name="ROBOTS" content="NOODP">
<meta name="robots" content="noodp">
<meta name="Robots" content="NoOdp">
If you have multiple content values, you must place a comma between them, but it doesn't matter if you also include spaces. So the following meta tags are interpreted the same way:
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
<META NAME="ROBOTS" CONTENT="NOINDEX,NOFOLLOW">
If you use both a robots.txt file and robots meta tags
If the robots.txt and meta tag instructions for a page conflict, Googlebot follows the most restrictive. More specifically:
- If you block a page with robots.txt, Googlebot will never crawl the page and will never read any meta tags on the page.
- If you allow a page with robots.txt but block it from being indexed using a meta tag, Googlebot will access the page, read the meta tag, and subsequently not index it.
Googlebot interprets the following robots meta tag values:
- NOINDEX - prevents the page from being included in the index.
- NOFOLLOW - prevents Googlebot from following any links on the page. (Note that this is different from the link-level NOFOLLOW attribute, which prevents Googlebot from following an individual link.)
- NOARCHIVE - prevents a cached copy of this page from being available in the search results.
- NOSNIPPET - prevents a description from appearing below the page in the search results, as well as prevents caching of the page.
- NOODP - blocks the Open Directory Project description of the page from being used in the description that appears below the page in the search results.
- NONE - equivalent to "NOINDEX, NOFOLLOW".
As defined by robotstxt.org, the following direction means NOINDEX, NOFOLLOW.
<META NAME="ROBOTS" CONTENT="NONE">
However, some webmasters use this tag to indicate no robots restrictions and inadvertently block all search engines from their content.
Update: For more information, please see our robots meta tag documentation.
salam every one, this is a topic from google web master centrale blog: Update on October 15, 2008: For more recent news on links, visit Links Week on our Webmaster Central Blog. We're discussing internal links, outbound links, and inbound links.
This table also provides the total number of external links to your site that we have available to show you.
When in this summary view, click the linked number and go to the detailed list of links to that page.
When in the detailed view, you'll see the list of all the pages that link to specific page on your site, and the time we last crawled that link. Since you are on the External Links tab on the left, this list is the external pages that point to the page.
Finding links to a specific page on your site
To find links to a specific page on your site, you first need to find that specific page in the summary view. You can do this by navigating through the table, or if you want to find that page quickly, you can use the handy Find a page link at the top of the table. Just fill in the URL and click See details. For example, if the page you are looking for has the URL http://www.google.com/?main, you can enter “?main” in the Find a page form. This will take you directly to the detailed view of the links to http://www.google.com/?main.
Viewing internal links
To view internal links to pages on your site, click on the Internal Links tab on the left side bar in the view. This takes you to a summary table that, just like external links view, displays information about pages on your site with internal links to them.
However, this view also provides you with a way to filter the data further: to see links from any of the subdomain on the domain, or links from just the specific subdomain you are currently viewing. For example, if you are currently viewing the internal links to http://www.google.com/, you can either see links from all the subdomains, such as links from http://mobile.google.com/ and http://www.google.com, or you can see links only from other pages on http://www.google.com.
Downloading links data
There are three different ways to download links data about your site. The first: download the current view of the table you see, which lets you navigate to any summary or details table, and download the data in the current view. Second, and probably the most useful data, is the list all external links to your site. This allows you to download a list of all the links that point to your site, along with the information about the page they point to and the last time we crawled that link. Thirdly, we provide a similar download for all internal links to your site.
We do limit the amount of data you can download for each type of link (for instance, you can currently download up to one million external links). Google knows about more links than the total we show, but the overall fraction of links we show is much, much larger than the link: command currently offers. Why not visit us at Webmaster Central and explore the links for your site?this is a topic published in 2013... to get contents for your blog or your forum, just contact me at: devnasser@gmail.com
You asked, and we listened: We've extended our support for querying links to your site to much beyond the link: operator you might have used in the past. Now you can use webmaster tools to view a much larger sample of links to pages on your site that we found on the web. Unlike the link: operator, this data is much more comprehensive and can be classified, filtered, and downloaded. All you need to do is verify site ownership to see this information.
To make this data even more useful, we have divided the world of links into two types: external and internal. Let's understand what kind of links fall into which bucket.
What are external links?
External links to your site are the links that reside on pages that do not belong to your domain. For example, if you are viewing links for http://www.google.com/, all the links that do not originate from pages on any subdomain of google.com would appear as external links to your site.
What are internal links?
Internal links to your site are the links that reside on pages that belong to your domain. For example, if you are viewing links for http://www.google.com/, all the links that originate from pages on any subdomain of google.com, such as http://www.google.com/ or mobile.google.com, would appear as internal links to your site.
Viewing links to a page on your site
You can view the links to your site by selecting a verified site in your webmaster tools account and clicking on the new Links tab at the top. Once there, you will see the two options on the left: external links and internal links, with the external links view selected. You will also see a table that lists pages on your site, as shown below. The first column of the table lists pages of your site with links to them, and the second column shows the number of the external links to that page that we have available to show you. (Note that this may not be 100% of the external links to this page.)
This table also provides the total number of external links to your site that we have available to show you.
When in this summary view, click the linked number and go to the detailed list of links to that page.
When in the detailed view, you'll see the list of all the pages that link to specific page on your site, and the time we last crawled that link. Since you are on the External Links tab on the left, this list is the external pages that point to the page.
Finding links to a specific page on your site
To find links to a specific page on your site, you first need to find that specific page in the summary view. You can do this by navigating through the table, or if you want to find that page quickly, you can use the handy Find a page link at the top of the table. Just fill in the URL and click See details. For example, if the page you are looking for has the URL http://www.google.com/?main, you can enter “?main” in the Find a page form. This will take you directly to the detailed view of the links to http://www.google.com/?main.
Viewing internal links
To view internal links to pages on your site, click on the Internal Links tab on the left side bar in the view. This takes you to a summary table that, just like external links view, displays information about pages on your site with internal links to them.
However, this view also provides you with a way to filter the data further: to see links from any of the subdomain on the domain, or links from just the specific subdomain you are currently viewing. For example, if you are currently viewing the internal links to http://www.google.com/, you can either see links from all the subdomains, such as links from http://mobile.google.com/ and http://www.google.com, or you can see links only from other pages on http://www.google.com. Downloading links data
There are three different ways to download links data about your site. The first: download the current view of the table you see, which lets you navigate to any summary or details table, and download the data in the current view. Second, and probably the most useful data, is the list all external links to your site. This allows you to download a list of all the links that point to your site, along with the information about the page they point to and the last time we crawled that link. Thirdly, we provide a similar download for all internal links to your site.
We do limit the amount of data you can download for each type of link (for instance, you can currently download up to one million external links). Google knows about more links than the total we show, but the overall fraction of links we show is much, much larger than the link: command currently offers. Why not visit us at Webmaster Central and explore the links for your site?
salam every one, this is a topic from google web master centrale blog:
We occasionally get questions on the Webmaster Help Group about how webmasters should work with Adobe Flash. I thought it would be worthwhile to write a few words about the search considerations designers should think about when building a Flash-heavy site.
As many of you already know, Flash is inherently a visual medium, and Googlebot doesn't have eyes. Googlebot can typically read Flash files and extract the text and links in them, but the structure and context are missing. Moreover, textual contents are sometimes stored in Flash as graphics, and since Googlebot doesn't currently have the algorithmic eyes needed to read these graphics, these important keywords can be missed entirely. All of this means that even if your Flash content is in our index, it might be missing some text, content, or links. Worse, while Googlebot can understand some Flash files, not all Internet spiders can.
So what's an honest web designer to do? The only hard and fast rule is to show Googlebot the exact same thing as your users. If you don't, your site risks appearing suspicious to our search algorithms. This simple rule covers a lot of cases including cloaking, JavaScript redirects, hidden text, and doorway pages. And our engineers have gathered a few more practical suggestions:
If you have other ideas that don't violate these guidelines that you'd like to ask about, feel free to ask them in the Webmaster Help Group under Crawling, Indexing, and Ranking. The many knowledgeable webmasters there, along with myself and a cadre of other Googlers, will do our best to clear up any confusion.
Update: See our additional blog posts about Flash Indexing at Google.this is a topic published in 2013... to get contents for your blog or your forum, just contact me at: devnasser@gmail.com
We occasionally get questions on the Webmaster Help Group about how webmasters should work with Adobe Flash. I thought it would be worthwhile to write a few words about the search considerations designers should think about when building a Flash-heavy site.
As many of you already know, Flash is inherently a visual medium, and Googlebot doesn't have eyes. Googlebot can typically read Flash files and extract the text and links in them, but the structure and context are missing. Moreover, textual contents are sometimes stored in Flash as graphics, and since Googlebot doesn't currently have the algorithmic eyes needed to read these graphics, these important keywords can be missed entirely. All of this means that even if your Flash content is in our index, it might be missing some text, content, or links. Worse, while Googlebot can understand some Flash files, not all Internet spiders can.
So what's an honest web designer to do? The only hard and fast rule is to show Googlebot the exact same thing as your users. If you don't, your site risks appearing suspicious to our search algorithms. This simple rule covers a lot of cases including cloaking, JavaScript redirects, hidden text, and doorway pages. And our engineers have gathered a few more practical suggestions:
- Try to use Flash only where it is needed. Many rich media sites such as Google's YouTube use Flash for rich media but rely on HTML for content and navigation. You can too, by limiting Flash to on-page accents and rich media, not content and navigation. In addition to making your site Googlebot-friendly, this makes you site accessible to a larger audience, including, for example, blind people using screen readers, users of old or non-standard browsers, and those on limited low-bandwidth connections such as on a cell phone or PDA. As a bonus, your visitors can use bookmarks effectively, and can email links to your pages to their friends.
- sIFR: Some websites use Flash to force the browser to display headers, pull quotes, or other textual elements in a font that the user may not have installed on their computer. A technique like sIFR still lets non-Flash readers read a page, since the content/navigation is actually in the HTML -- it's just displayed by an embedded Flash object.
- Non-Flash Versions: A common way that we see Flash used is as a front page "splash screen" where the root URL of a website has a Flash intro that links to HTML content deeper into the site. In this case, make sure there is a regular HTML link on that front page to a non-Flash page where a user can navigate throughout your site without the need for Flash.
If you have other ideas that don't violate these guidelines that you'd like to ask about, feel free to ask them in the Webmaster Help Group under Crawling, Indexing, and Ranking. The many knowledgeable webmasters there, along with myself and a cadre of other Googlers, will do our best to clear up any confusion.
Update: See our additional blog posts about Flash Indexing at Google.this is a topic published in 2013... to get contents for your blog or your forum, just contact me at: devnasser@gmail.com