When signing up for popular services like Twitter and YouTube, you may have allowed the default email notifications or selected some options and never went back to change them. If now you're getting more updates and notifications than you'd like, Notification Control can help you clean them all up quickly.
Like previously mentioned MyPermissions, Notification Control is just a starting page -- a useful bookmark to popular web apps' email notifications settings pages. It doesn't access your account credentials at all, but rather just takes you where you need to go to manage things like what sort of updates you want to get via email from Facebook.
Services covered right now are: Twitter, Facebook, Tumblr, YouTube, Foursquare, LinkedIn, Pinterest, Google+, Meetip, Dribbble, Ebay and Forrst.
It takes just a minute to get your email notifications the way you want them. Add this along with the MyPermissions bookmarks page and you've got a web services cleanup launchpad, so to speak.