What Is Unity Online Search Feature?
The Unity search function in Ubuntu operating system is provided by Canonical Ltd. When you enter a search term into the dash, Ubuntu will search your computer and will record the search terms locally. Unless you have opted out, the search terms will be sent to productsearch.ubuntu.com link and selected third parties including Facebook, Twitter, BBC, and Amazon. Canonical and these selected third parties will collect your search terms and use them to provide you with search results while using Ubuntu.
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How To Disable Unity Online Search Feature On Ubuntu 14.10 (Unixmen)