When Facebook announced its new location-based capabilities after Twitter has already enabled it, the future looked pretty grim for Foursquare. Though wildly popular with the nerd crowd (of which I'm a member ... the nerd world, not Foursquare), could a year-old location-based game go head-to-head with the 400 million-user-strong behemoth of the social media industry? In a strange twist, Facebook is actually breathing life into the killer app many expected it to kill.

Thirty-three percent of Foursquare's traffic comes from Facebook, according to data from Hitwise (EXPN), followed by Google (GOOG) at 22% and Twitter at 8%. The remaining one third of traffic, from everyone else, is fed in part by partnership with major brands such as the New York Times (NYT), Bravo and Zagat.

As the founders of the Zagat Survey, Tim and Nina Zagat's financial futures are pretty directly tied to the future of the restaurant industry.

Bias aside, they make a pretty compelling case for bullishness on the restaurant industry in an op-ed piece in today's Wall Street Journal. A recent Zagat survey found that one-third of Americans are eating out less, 28% say they are visiting less-expensive places, and 20% are cutting back on alcohol, appetizers and dessert.

But in the long term, the Zagats are bullish: Americans like eating out, cooking at home has gone the way of the hula hoop, and we're busier than ever. A few bad quarters aside, the long-term outlook is what matters and the future for restaurants still looks good. Better still, economic weakness has slowed restaurant expansion and resulted in more than a few closing, which bodes well for the surviving players.

But for now, the share prices of most restaurant stocks have been absolutely pulverized, making them an interesting long-term contrarian investment possibility. Earlier this month, I wrote about some beaten-down restaurant stocks that might be a good buy.

Back in January, Zagat Survey looked for a buyer. Apparently, the cofounders -- Tim and Nina Zagat – wanted to get $200 million (hey, who wouldn't?). But, with the credit crunch, it did look somewhat optimistic even though the company has a great brand.

Well, the Zagat's investment bank, Goldman Sachs (NYSE: GS), wasn't able to get any buyers at the proposed valuation. I guess there just wasn't enough conviction that Zagat could leverage its dot-com/mobile platform.

Actually, if Zagat attempted a sale a year before, things might have been much different. But, instead the company will need to wait until markets bubble up again, which may take awhile.

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Edgar Online Guide to Decoding Financial Statements. He also operates MergerBook.com.