Scout is a passive app which allows you to know when your friends are in a certain geolocation. The best explanation is always an example so here you go.

You're on a college campus but don't know whos around. You have 3 choices.

A) Text each of your friends (That's annoying for you)
B) Send to a group chat (That's annoying for them, also who said you want to hang with any of those people)
C) Open scout.

C seems like the best option.

Once you open scout, your informed of all your friends who are currently in the set location. Once you know who's on campus, send them a text to hang out.

1, 2 and no 3. It's that easy