My thoughts on Facebook's pulled employee stock sale

As reported by the Wall Street Journal, Facebook has pulled its planned employee stock sale. This would have allowed the 800+ employees of Facebook to sell a portion of their stock to private investors - supposedly $900,000 worth or 10% of vested shares, whichever is less. Reasons that some outlets are stating was that Facebook couldn't find any private investors who wanted to buy the stock at a company valuation of $4 billion - a far cry from the $15 billion valuation Microsoft got for its $240 million investment.
I'm not really shocked that there were no takers at $4 billion. At the time of the original Microsoft investment, I thought Facebook's value was somewhere around $7 - $8 billion. Then when Techcrunch got a hold of some internal financials, I did a back of the envelope recalculation and stated that they should be valued at $4.5 - $5.25 billion which is 15 times projected 2008 revenues. Contrast that with Yahoo or Google which are valued at 2.19 and 4.13, respectively. These have gone down some recently but even if you calculate at January 2008 share prices, Yahoo and Google would still only trade at 4.44 and 10.91 times revenue, respectively. You can make the argument that these are more mature, slower growing companies but these are also PROFITABLE companies - in the case of Google, VERY PROFITABLE. Facebook, on the other hand has huge capital expenditures for servers/bandwidth ($200 million according to Techcrunch) and a hard to monetize audience. They may be GAAP profitable or break-even but most definitely not cash flow positive. Given the eventual slowdown in the online advertising market, I don't think it will get easier for them to squeeze more revenue from their users. However, the cost to support their growing legion of users is going to grow as they'll need more servers and bandwidth.
With that said, my new calculation of Facebook's value would only be at best 5 times revenue or $1.5 - $1.75 billion. Of course if they had allowed the employee sale to reset the value of their company, I doubt they'd raise enough through an eventual IPO to cover their growing capital expenditures. The more important question is, how much of the $516 million that they've raised is still there? My guess is that if they can't raise another $100+ million round soon, Facebook could be in for some tough times.