Tinder is a dating app that uses location services in conjuction with a facebook profle (updated to also include instagram). Tinder utilizes the users name, age, profile pics and any pages that have been liked on facebook. Then, based on the location, potential "matches" are sent. Users have the option to "like" or "pass". If the user "likes", then the two users can start messaging each other. Users do not get results on who has "passed" on them, only who has liked, giving the user a sense of instant gratification.
Though this is set up as a dating app, tinder is open to users aged 13 and over. It would be quite easy for someone to set up a fake profile, leaving youth open to luring from predators.