In the upcoming Lucid Lynx (10.04) release of Ubuntu, the default search provider in Firefox will change from Google to Yahoo!. This is a result of a revenue sharing deal between Canonical and Yahoo!.
https://lists.ubuntu.com/archives/ubuntu-devel/2010-January/030065.html

Yahoo! search is powered by Microsoft's bing. It was observed on Slashdot that Microsoft will be indirectly paying for Linux.
http://linux.slashdot.org/story/10/01/27/0118244/Ubuntu-Moves-To-Yahoo-For-Default-Firefox-Search?from=rss&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Slashdot%2Fslashdot+%28Slashdot%29&utm_content=Google+Feedfetcher

I've never used the default search page of Ubuntu anyway, even I use Google.
Also isn't that a bad deal for Microsoft, I think like 90%, if not more, of the Ubuntu users are experts and for sure they know how to switch and will switch back to Google, don't you think so?

The homepage for my Firefox is still the Ubuntu Search page, but I rarely use it. Even if I want to search for something as soon as I open the browser I'd go to the search bar as I don't like the custom search page.

Also I'm using Chrome more and more, so unless Canonical bundle Chrome and change the default homepage, this probably won't affect me.

<< Yahoo! search is powered by Microsoft's bing. >>

No, not yet. Since Microsoft licensed Yahoo's search technology, Bing will use Yahoo Search.

Compare:

http://www.bing.com/search?q=ipad&form=OSDSRC
http://search.yahoo.com/search;_ylt=A0geu7R4lGBLbgYAWVCl87UF;_ylc=X1MDMjE0MjQ3ODk0OARfcgMyBGZyA3NmcARmcjIDc2J0bgRuX2dwcwMxMARxdWVyeQNpcGFk?p=ipad&fr=sfp&fr2=&iscqry=

and

http://www.google.com/webhp?hl=en&q=ipad

Yahoo shows many results about iPod, Bing has a lot of irrelevant results, while Google has recent news about Apple's latest gadget.