Never used a gay app.
Since i am still "in the closet", i am too afraid to use such apps and ended up exposing to my friends and family my sexual preferences.
I don't know how these apps work, but i do think that, once you create a profile in these services, your cel number, localization and other sensitive information will be out on the wild, allowing anyone to be able to find you and discover your most hidden secrets.
I really don't have the courage necessary to use them.
Plus, i live in a very small town and rarely leave the city. Would probably be a waste of time trying to find someone from other places, and too risky trying to find someone near me.
If someone has more information regarding whether it's possible to keep your privacy and ID very secure, i would love to know more.