Besides, the feature as currently implemented in Ubuntu 12.10 "isn't the full experience, so those who leap to judgment are at maximum risk of having to eat their words later," Shuttleworth added. "Chill out."

The Amazon results are not ads, he stressed, since they're not paid placements.

As for privacy concerns, users' anonymity is preserved because Ubuntu handles queries on their behalf, he said.

"Don't trust us? Erm, we have root," Shuttleworth noted. "You do trust us with your data already. You trust us not to screw up on your machine with every update. You trust Debian, and you trust a large swathe of the open source community. And most importantly, you trust us to address it when, being human, we err."