What the dilly-o? Microsoft are contacting website owners to tell them how bad their pages look in IE8? Have they not considered looking for the problem somewhat closer to home? I develop standards compliant web sites and applications and, without fail, IE8 is the only recent browser that does not render any of them correctly (and we test sites in IEs 6, 7 and 8, Firefoxes 1, 2 and 3, Safari 3 for Mac and Windows, Opera 9 and Google Chrome).
I understand them stating that their "standards compliance" is a reason why pages designed only for Internet Explorers 7 and earlier may not render correctly, but this cannot extend to pages that were written to be standards compliant in the first place. It makes me wonder about precisely what standards Microsoft think they are following.