Just two months Canonical had announced its decision to change Default Search Provider in Ubuntu Version 10.04 to Yahoo.
Now, Canonical has decided to switch back to Google Search. The final release of Ubuntu 10.04 will have Google as default search in Firefox Web Browser.

Rick Spencer from Canonical explains the reason behind sudden change

“However, for the final release, we will use Google as the default provider. I have asked the Ubuntu Desktop team to change the default back to Google as soon as reasonably possible, but certainly by final freeze on April 15th.

It was not our intention to “flap” between providers, but the underlying circumstances can change unpredictably. In this case, choosing Google will be familiar to everybody upgrading from 9.10 to 10.04 and the change will only be visible to those who have been part of the development cycle for 10.04.”