Google is now targeting the ads it shows you. It does this by tracking your google-related activities. That includes any sites you visit that display google-based ads (AdSense), which is a lot of sites.
Me, I don’t want to be tracked. If you feel as I do, go here to learn how to opt out.
I just noticed, as I was typing out a message through gmail.com, that Google has a little note at the bottom that tells you the IP address of the last login, and I think the IP’s of each reply throughout the whole thread of the email.
I’m not really that savvy with things that are too far behind the scenes in regards to the workings of internet protocol, but I would just assume play it safe and not have things like that tracked. Gmail already keeps every message you send indefinitely… What if twenty years down the road, and an old vitriolic fit of passion email comes back to haunt you?
Thanks for that link.