Keeping track of changes to terms of service or privacy policies on websites is incredibly difficult, because they change so frequently. Paranoid Paul is a web app that let's you pick services and get alerts when the policy changes.
All you need to do is enter in the websites you want to get updates from, add them to a watch list, then enter in your email address. When a site's policy changes, you'll get an email with all the details. It's a pretty simple way to keep up to date with the policies of sites you're using without reading every single one every time.