Tinder has to get into creating real revenue some day. Tinder plus seems to be their answer - a paid service with more features. One of those being a "undo button" that lets you revert an accidental or too quick "swipe left". It will be interesting to see wether a Tinder plus will work as long as "real dating" will be possible with the free version. Typically the freemium model is based on the idea of delivering a limited experience, In Tinder's case that could be a limited amount of messages or matches a day; they seem to choose a different direction.