I went to
The W3C Markup Validation Service and checked my site, and it returned 85 errors. So I checked Yahoo, Google, Ebay, iLike (pure CSS site) and various other sites and they all return errors.
Who uses this thing? Everyone seems to rave about how you need to check for errors and whatnot, but if the big guns are doing just fine (heck, even a pure CSS site returned errors and they're using the latest technology), then what's the point of validating with W3.org or validating period?