Not really sure what you mean. This is the way just about every, no, every single online store is rendered. The only outlier until this morning was iTunes, which for some obscure reason (legacy, historical) chose to have proprietary XML and a proprietary renderer. If anything, this is what should have been done ages ago, considering they invented all this technology.
Arguably, the store continues to be hindered by not being web enough. I've often wanted to have multiple tabs since (gasp) I may want to look at more than just one item simultaneously. Its also still difficult and confusing to send links to iTunes pages to people. Individual items are a bit easier with iTunes 9, but linking to the "Movies" section, not so much.
Pretty damn impressive because it's gorgeous. Most online stores look like they're made out of HTML. iTunes looks wholly different. It's a reminder to me as a designer that the web is capable of handling much more than I put it through at the moment.
The page rendered in Webkit-compatible HTML. Pretty damn impressive on Apple's part.