67. About Gmail and Privacy
In some of your incoming email, you might notice sponsored links on the right side of the pagethese links are essentially advertising. These ads are not random; they are related to the content of the message itself. Not all emails have sponsored links. A message from your friend about his ten-year-old son's grades might not have sponsored links, while a message from someone about buying office equipment might have links to sites that sell office furniture. The nearby figure shows an example of those links.
An example of sponsored links inside an email message.
How do those sponsored links end up there? Google examines all your incoming email, and if it finds certain words, it places sponsored links in your email messages. This works in the same way Google searches dowhen you do a Google search, Google looks at the search terms, and if it finds certain words, it places sponsored links in your search results.
At first blush, it might seem as if having Google examine your mail is an invasion of your privacy. But there's less here than meets the eye. First of all, no people read your mail; software parses through it looking for search terms. Secondly, Google isn't doing anything that different from what your normal email ISP does.