Interesting article here about Google and how they do markup on their search page.
Apparently, they have determined that not closing the <body> and <html> tags on their pages somehow has a performance benefit, and so ignore what most people would consider to be Markup 101 (not to mention the other ‘issues’ mentioned there).
I wonder how long it will be till someone brings up this issue to me as a reason why markup validation doesn’t matter.
When building an e-Com system, my business partner and I have at some point in the past come up with the conclusion that just because Amazon does something, doesn’t necessarily mean it is a good practice to follow. I think the same can be said about eBay, Google, <insert mammoth system here>, etc.
I’m still going to try to write valid markup when I can.