> Whoever wants to replace OpenTable needs to replace all of this at once. Not only that, they need to convince a restaurant to ditch practically their entire IT stack, retrain all of their employees in the new system, and do so without service or quality interruption.

Yelp acquired SeatMe[0] (front of house management) last year to expand into this market, and Yelp Reservations[1] was launched last month. These two products combined function as an OpenTable replacement.

Disclaimer: I work at Yelp.

[0] https://www.seatme.yelp.com/

[1] http://officialblog.yelp.com/2014/05/yelp-reservations-new-f...