FB as your only sign up option was one the main reasons for Tinder’s steadfast growth trajectory. Tinder as the guest list for sister sorority parties. Had to download the app in order to get in. Which was possible because the founders were in the sororities. They’d go to the corresponding brother fraternity—they’d open the app and see all these cute girls..they were onboard!. We had been picking up on college campuses, then everyone went home and told their cousins and older brothers and friends about it, and all of a sudden Tinder started growing like a virus.