Tim Mayer of Yahoo! was the guest on Barry Schwartz's Search Pulse show last evening. Barry has been lobbying Yahoo! to create a "No Yahoo! Directory" tag, as well as implementing the NOODP meta tag through his posts on Search Engine Round Table
Tim announced that next week Yahoo! will be implementing the NOODP tag, but for now, there won't be any "No Yahoo! Directory" tag.
Both Google and MSN (now Live.com) currently support the NOODP tag. If you are unfamliar with what this tag is, breifly, ODP stands for Open Directory Project. Sometimes, the search engines will choose to pull the description and title from ODP for a website, rather than using the Title & Meta Description the site already has set in place. The issue that webmasters have with this, is that the ODP editors might not get the marketing message right or if the site updates, ODP doesn't. Placing the NOODP tag in your header, prevents Google, MSN and soon Yahoo! from using that ODP Title and Description.
Currently these tag should be as such (minus the extra spaces before the "<" and ">")
< meta content="NOODP" name="ROBOTS" >
< meta content="NOODP" name="msnbot" >
< meta content="NOODP" name="googlebot" >
I'm with Barry, Yahoo! should have a way to "opt out" of it's Yahoo! directory listing in search.