You beat me to it by a whisker.
If the borg buys Yahoo, it's a pretty big deal - not sure if anyone has really grasped what this means yet.
Firstly it gives the combined entity 35% or so of the search engine market, which is still way behind Google, but at least it becomes significant. But additionally it gives a lot of control around advertising, particularly when you think about how the OS integration could be leveraged to force more ads down people's throats.
$46bn is a lot of cash though.
Yahoo has their fingers in other things, like namely flickr. I don't know how good or how bad this will be. There's already a thread in one of the larger groups on flickr about how the sky is falling. If they keep things without charging for the free services or raising the price on pre-exsisting services, then I don't think it could be too terribly bad.
In fact, I think that they may try and add some features, but they might not try and do too much to certain aspects of Yahoo to minimize disruptions. A lot of small businesses host their sites and shopping carts through Yahoo. I could imagine that they would rather collect the revenue rather than lose the customers.
The only thing I would want for them to keep the same is the development of apps for certain sites for other OS'es than MS. Flickr has the Downloader that's usable on MS, OS X, and Linux iirc.
I don't think they'd do too much to flickr since they have a ton of paying users.
Some one also mentioned that possible integration into the MS passport system might be a direction they would head in. Flickr was a seperate entity from yahoo, and then when they were bought, the flickr user profiles and id's got rolled into Yahoo ID's. I'm with him thinking that that may be the case with Yahoo ID's to MS passport ID's.