We found that Google has released updated guidlines (updated 12/16/2009) about this matter to support webmaster to prevent search engines from displaying DMOZ data in search results for their site. Bellowing is the detail information from Google.
One source we use to generate snippets is the Open Directory Project. You can direct us not to use this as a source by adding a meta tag to your pages.
To prevent all search engines (that support the meta tag) from using this information for the page’s description, use the following:<meta name="robots" content="NOODP">
To specifically prevent Google from using this information for a page’s description, use the following:<meta name="googlebot" content="NOODP">
If you use the robots meta tag for other directives, you can combine those. For instance:<meta name="googlebot" content="NOODP, nofollow">
Note that once you add this meta tag to your pages, it may take some time for changes to your snippets to appear in the index.
If you’re concerned about content in your title or snippet, you may want to double-check that this content doesn’t appear on your site. If it does, changing it may affect your Google snippet after we next crawl your site. If it doesn’t, try searching Google.com for the title or snippet enclosed in quotation marks. This will display pages on the web that refer to your site using this text. If you contact these webmasters to request that they change their information about your site, any changes to their sites will be recognized by our crawler after we next crawl their pages.
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