Yahoo has a new Robots-Nocontent tag and I doubt if that does not bring them more webspam.

When a “robots-nocontent” tag is used to mark a section of content on a web page, Yahoo! will not use the terms contained in that section as information for finding the page or for the abstract of that page in search results. Note: Using a “robots-nocontent” tag to mark explicit sections of content is not considered “cloaking” because all the content on the page is available to us (unlike “cloaking” where we may be served content that is different from what users see.)

The “robots-nocontent” tag is a useful tool for webmasters.

• It can improve our focus on the main content of your pages.
• It helps target your pages in search results by making sure the appropriate deep page in your site can surface for the right queries.
• It helps improve the abstracts for your pages in results by identifying unrelated text on the page and thus omitting it from consideration for the search result summaries.

When you successfully target your page content, it can increase the likelihood that the user will find your page, find it relevant, click on your result, and convert.  Read more here