Smashing Magazine, the uber-web design blog on the blogosphere, did a really nice study of the 50 most popular blogs (as ranked by Technorati) in terms of their design, information architecture, functionality, and so on.
Neatorama's mentioned in the article (thanks guys!) and the blog even won an award of sorts. It won an award for having one of the most markup validation errors! Actually, all of the blog surveyed have errors save one (A List Apart, but then you'd expect it of the web design experts). In reality, this sort of stuff is meaningless: even yahoo.com and google.com failed validations.
Anyways, Neatorama is old school - it's built with tables (why? Because tables are better than positional CSS, of course!) and that, my friend, is why it has so many validation errors.