The Future of Local Commerce = Facebook + Foursquare + Yelp + Groupon

There's been much hype, crazy valuations, and overall market excitement about businesses that promise to unleash the power of the social graph, location, recommendations and group buying. Facebook's latest valuation according to SecondMarket is now about $30 billion , Foursquare raised $20 million at a post-money valuation of $115 million while still at a pre-revenue stage, Yelp, short of selling for $550 million to Google, raised over $25 million at an undisclosed but very high valuation, and finally Groupon raised $135 million at a whopping $1.35 billion valuation. So besides their huge success with the investment community, and their users, what do these companies have in common, and what does all this have to do with disrupting Local Commerce? Editor's note : The following guest post is by David Marcus, founder and CEO of Zong, a mobile payment provider for Facebook Credits, AT&T and hundreds of leading destination websites and mobile applications