Wow - the big news of the day, is big news. There's plenty of commentary already (here, here, here) - no doubt there's a huge pile of money involved - but what's that worth if you loose one of you major platforms for innovation? It seems like Yahoo traded a whole lot of innovative stuff like BOSS and Search Monkey plus its organic search feed for a payout (maybe it's not the case and those products will live on).
The wierd thing is that everybody is trumpeting a Mircosoft win but to be honest in 10 years I think the search and (especially) the search based advertising space will have changed radically - in fact I'd be willing to be that the move from "web pages" to apps, widgets and feeds will be so strong the whole economics of the space will be redefined. Even if this buys Microsoft mometum now, the company which best masters this shift from full web pages to fragments and apps will be in the driving seat. Sadly it seems Yahoo's capacity for a shot at that space just got decimated!