Comment Would have been Firefox with clean installs only (Score 2, Interesting) 224
Do note that the Yahoo change was going to effect Firefox users. Konqueror, Arora and all other browsers users were not affected in the first place.
Also, if you upgraded from 9.10 to 10.04 and were using Google back in 9.10, Google stayed as your default search engine.
I think the real reason why Ubuntu went back to Google is because Google has too much branding over the idea of searching the web. Nobody says "just Yahoo! that". Shockingly enough, there are people who are new to the web and do not even know what Yahoo! is but has heard of Google. Remember, Canonical true goal is Linux on the desktop for everybody; even users who are new to computers.