SEO meta tags

Source

Search engines will sometimes opt to ignore them in favor of the
description used at Dmoz.org or in the Yahoo! Directory
(if you have a listing there).

To help webmasters control this scenario, new meta tag variations were
created to force
search engines to use the <meta> description tag instead of the
description found in the
directory listings. Here are examples that detail ways to block either
Dmoz.org or Yahoo! Directory descriptions:

<! -- Tells Yahoo! to not use Yahoo! Directory description -->
<meta name="robots" content="noydir" />

<! -- Tells search engines to not use ODP description -->
<meta name="robots" content="noodp" />

<! -- Tells search engines to not use either of the two directories -->
<meta name="robots" content="noodp,noydir" />

If you wish to target only specific spiders, you can do the following:
<meta name="googlebot" content="noodp">
<! -- Note: Only Yahoo! uses Yahoo! Directory -->

<meta name="slurp" CONTENT="noydir">
<meta name="msnbot" CONTENT="noodp">