Ubuntu uses the information about searches to show the user ads to buy various things from Amazon. Amazon commits many wrongs (see http://stallman.org/amazon.html); by promoting Amazon, Canonical contributes to them. However, the ads are not the core of the problem. The main issue is the spying. Canonical says it does not tell Amazon who searched for what. However, it is just as bad for Canonical to collect your personal information as it would have been for Amazon to collect it.
Same question has been asked here Ubuntu with spyware? But I don't have the tab 'search results' on my 12.04 distro. How can I disable this?
I understand that canonical uses this business plan in order to make a living and I really would help in their research as long as the data is preserved anonymously, but I really want to have control over this option, so when I search for something to buy, then enable it so I can help canonical gather this data, otherwise I would like this option disabled.