It was silently introduced into the build of Karmic Koala which is scheduled for release in October as version 9.10.
However, once users started raising their voices on the Ubuntu forums, the Ubuntu team backed down, in an equally inconspicuous way, which would have gone unnoticed but for the fact that the energetic folk at Linux Weekly News picked up on it.
Custom search pages are a way of generating revenue for the company that provides the search facility, in this case Google.
The chief technical officer of Canonical, Matt Zimmerman, in a post to the LWN forums, offered this explanation: "As explained in the bug report and elsewhere, this "feature" was a strictly time-limited experiment to collect data. It's been deactivated precisely on schedule, having been planned to be active between Alpha 3 and Alpha 4 in the 9.10 development branch."
However, as another poster, coriordan pointed out, "It was put in silently, and when it was discovered, the maintainer said it was put in 'at least until Alpha 4'. If no one complained, I don't see anything to indicate that there was any plan to remove it before the general release.
"Where did they say it was 'strictly time-limited', and what was the date set for its removal? If they say they won't do it again, I'm happy to forget all this as a mistake, but let's not get revisionist already."
There was no response to this post from Zimmerman.