You know the question the VCs always ask: "What if google decided to attack your market, what would you do?" I guess it's a sad day for a couple of promising startups.
I can't think of a single example of a company that actually became more popular and relevant when the same thing happened.
(Yeah, okay, Adobe isn't exactly a small company. But they're a lot smaller than Microsoft, but Dreamworks has consolidated its position, and Microsoft killed off Frontpage...)