Most social media users don't realize how much of their information they allow 3rd party apps to access. It is such a problem that I use IFTTT to send me a monthly reminder to check my social media security settings.

My recommendation is to use MyPermissions and I recommend you read my write-up here. It takes 5 minutes each time and it is time well spent.

If there are any accounts you want to close, take a look at AccountKiller, a neat site that shows you (step by step) how to delete your account from the most popular sites on the internet.