How to find out everything Facebook-login apps know about you
Deleting it doesn't necessarily rescind the permissions you granted to the app to watch your Facebook activity.
So, once in a while, it's a good idea to look at the apps that have access to your Facebook and tell Facebook to stop sharing stuff with the ones you are no longer using.
Finding this stuff on Facebook isn't obvious, but it isn't terribly hard either.
There are two options. The first is a "privacy checkup." Click on the small "settings" button on the top right of your screen. It looks like a lock.
Click on "Next step."
Click on "App Settings."
You can also get to this page by clicking on the App Settings link on your main Settings page. (Settings/More Settings and then "Apps" on the left hand side of the page).
Once you are on the Apps Settings page, click on "Show All."
I saw a bunch of apps I haven't used in ages, and one called Photo Viewer that I couldn't even remember using.
To tell Facebook to stop sharing your info, remove the app by clicking on the "x" next to the app.
You can also check out exactly what info Facebook is sharing with any app (i.e. everything the app knows about you) by clicking the "edit" button. In the picture above, That's the pencil next to the "X."
For instance, an app I had never heard of collected all my information and watched everything. It "required" me to share my newsfeed posts, my relationships, everything. I deleted it.
I checked on other apps, and made I was ok with the things I was sharing.
Best of all, I now knew the full list of apps that I used my Facebook login.