If you don't specify a search description for your blog, search engines will establish one for you based on your blog’s content.
To create your own search description, just go to Settings | Search Preferences and click Edit next to "Description" to reveal a text field. Select Yes, write in your text, and click Save changes.
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A few examples of blog search descriptions:
- “A blog about social networking and web design.”
- “A journal of my year in Paris.”
- “Healthy southern-style cooking.”
Enabling this feature will display a “Search Description” option in the Post Settings panel that allows you to enter a search description for individual posts.
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For more background on SEO, read through this article in the Webmasters Help Center, and be sure check out their SEO Starter Guide (pdf.
Read more: http://support.google.com/blogger/?hl=en