Sorry, you're wrong.
Google purportedly just offered Groupon $5 billion. That's my best estimate of Groupon's probable market cap.
SecondMarket just did an auction of stock in a company whose sole asset are some shares in Facebook. Based on this, my best estimate of Facebook's market cap is $50 billion. (See http://www.pcmag.com/article2/0,2817,2373614,00.asp for more on that auction.)