[macavity23]

In terms of affecting what devs need to do, it doesn't matter. However, if it happens (and it's a big if), it would certainly be noteworthy, because it will cement html standards-compliance.

As you say, you need to support IE, Chrome, FF and Safari - but (at least for IE < 8) this has always meant supporting the standard and then tweaking it to make it work in IE. I've never had significant differences in webpage functionality between chrome, FF and safari (YMMV). IE 9 is MUCH better at standards compliance - but this is purely because of MS's losses in marketshare.

If you don't see this as a significant thing, then I'm guessing you're too young to have been coding web pages when IE had a 90%+ market share. You kids have it easy. :-)