I know Andy Beal reported this, but I think its important to mention on as many sites as possible.
Bottom Line: Unique Meta Keywords and Meta Descriptions for each page of your Web site.
At WebmasterWorld, Tim Mayor from Yahoo says "Yahoo Search uses the Metakeywords tag . We did not use them at FAST or Altavista. It is important that you make the keywords and description different (targeted) on every page. Exactly what the page is about. ie. the right specificity. Having all the pages have the same keywords and description is not helpful to the SE." This thread can be found at WebmasterWorld.
Thanks Andy for pointing it out.