As a lot of people are talking about, the new MLA handbook has ditched the URL component of citing web sources. It seems that this is part of a general web-friendly shift (online content adds to the book, etc.). While the online-only parts of the book seems sketchy, to me, the revision of the citation standards is more than welcome. The Internet citation system was always glitchy, at best.
I remember once citing a Deleuze article in a seminar paper and got the thing back with the citation (which was "(Deleuze)") circled with the comment "Did you forget the page numbers?" Sigh.
Hopefully, the new manual makes this a lot clearer and less painful.