Google’s privacy practices are occasionally in the media, and Gmail hasn’t avoided the questions of how the search engine giant treats your messages. There have been a number of html gmail alarmist articles about Google spying on its users, so I think it’s only reasonable to put this into perspective and discuss how the company is actually using your mailbox.
In a nutshell, Google is not reading your messages nor is it sharing them with anyone else. However, there are processes that do read your mail in order to eliminate spam. In order to provide a free service, Gmail also displays ads on a sidebar, and this is also a source of consternation. Unlike other mail providers which provide ads regardless of message content, Google scans for keys and displays targeted ads. This works in much the same way as the ‘Sponsored Links’ sidebar in Google Search – those ads are selected for relevance in the hope that you will find them useful (and therefore click one).
So if your last five messages relate to booking a flight to Italy, you will likely see ads for flights, travel or attractions in Italy. The algorithm is smart enough to ensure ads are family-safe and sensitive – for example, if you announce a funeral, you won’t see any ads. Ads are never attached to emails and do not bind with your message data in any way. Most importantly, Google doesn’t read your messages, share them with anyone else, or provide any of your data to advertisers and third parties.