Callback URL for twitter app

[nilamo]

Generally, these are if you're pretending to be someone else. Like, you open a link to Twitter (with a callback url), and then whoever's using your app will log into Twitter using whatever their credentials are. Once they're done, they'll be redirected to your callback url with some sort of short-term access token which you then use with the api, to make calls for that particular user.

The whole point of this, is allowing random third party apps (like what you're making) access user data, without ever having access to that user's login/password.