OpenTable also has their equivalent offering:
<a href="http://spotlight.opentable.com/deal/los-angeles/losangeles25" rel="nofollow">http://spotlight.opentable.com/deal/los-angeles/losangeles25</a><p>More competition drives the group-buying model to a more sustainable proposition for local businesses.
Yelp already is one of the 45th most trafficked website in the US (Alexa). With millions of users already on the site with the intent of finding a restaurant, bar, mechanic, spa etc., adding a daily deal and leveraging their traffic makes sense. How much should groupon worry?