Privacy is not an issue with Unity's shopping lens, since Amazon cannot identify you apart from anyone else. If you don't want your search queries to leave your computer at all, then don't use a global search box (just like you don't type those queries into Google, either).
"We are not telling Amazon what you are searching for. Your anonymity is preserved because we handle the query on your behalf." --Mark Shuttleworth, http://www.markshuttleworth.com/archives/1182
Once again, "you can opt out" isn't a serious answer. It's a matter of policy to anonymize the data, and Canonical changes policies unilaterally. The feature isn't under the control of users at all, and that is why it's dangerous.
Canonical has made it abundantly clear that their users have no voice in the development of Ubuntu, in fact they've been quite hostile when confronted with their secretive and authoritarian development practices.
This seems undeservingly harsh. They have an opt-out system and that's "over the barrel"? If so, then if they were to hypothetically sell a users' list of most popular apps they ran or something like that, what would they be doing to the user and how would the barrel be used?
>Privacy is a serious question for businesses, and "you can opt out" isn't a serious answer.
It is a serious question for everyone and you provided no explanation other than your opinion as to why "you can opt out" isn't a "serious answer"
"We are not telling Amazon what you are searching for. Your anonymity is preserved because we handle the query on your behalf." --Mark Shuttleworth, http://www.markshuttleworth.com/archives/1182