I was using Gmail the other day and I noticed that the ads kicked in. I did not have ads on my account for a long time. They are not annoying or anything. They sit on the right side of the screen and they are related to the content of your emails. This caused some controversy when Google first said they would target ads based on email content because people did not want their messages scanned.
It does not bother me. I certainly want to protect my privacy but email is all sent in plain text unless you use PGP or some other encryption. The main this is to remember what to really keep in email. Email is not a storage system, it is a communication method. As long as they do not profile me and then sell it. I actually clicked on one of the advertising links too. It was not an accident. I noticed the ads and then one of them was for information on the Shinkansen so I went there. I was just thinking of looking for more information on the trains and this time I did not even have to search for it. I doubt I will be “using” the ads often but at least they are relevant and not disturbing. Yahoo’s ads are terrible and Hotmail’s are flashy. These are just text.