Curiosity got the best of me this morning when I got on my Ubuntu machine. When I looked to the address bar and was about to type in the address, I remembered that Ubuntu 10 was in development, and wondered what the start page would look like. So I went to http://start.ubuntu.com/10.04/ and was quite surprised to find that it had Yahoo! Search written in place of the regular Google banner. After a quick Google search, I then found out what was happening. It seems that according to http://lwn.net/Articles/371358/ that Canonical (which runs the development of Ubuntu) has worked out a sharing deal with Yahoo in order to provide more development resources for the future development of Ubuntu. This deal seems rather surprising however considering that Yahoo and Bing just made a deal stating that Yahoo will just be delivering Bing results.
Luckily, if you do not like Yahoo, the default page will change based on your browsers default search settings.