I think that groupon should work to build an alliance with yelp or that they should consider a merger. I personally don't use groupon and don't particularly like the discounts they offer (i've viewed their options pretty regularly because i'm cheap.)

Yelp would've been a great fit with groupon because they both focus on local niche markets. Yelp often allows clients to offer discounts if the customer mentions "yelp." A great way for yelp to monetize their huge market and crowd-sourced reviews would be to allow individual business develop groupon like mini promotions.

I wouldn't be surprised if this type of product would help generate an entirely new level of revenue for both companies.

Its ironic that neither company has thought of this.