And we're back again with our now weekly update on the insanity surrounding Facebook's stock in the SecondMarket auctions. Last week , the stock saw the beginning of a rally back to $27 a share, good for a $67.5 billion valuation (based on roughly 2.5 billion shares outstanding). This week, the good times continued to roll. Facebook's stock hit $28 a share, to push the valuation of the company back to a cool $70 billion or so. This is still slightly off the record high of $28.26 a share (a $70.65 billion valuation ) set in mid January, but it's clear that Facebook's stock is storming ahead once again, and quickly. This was the 11th auction SecondMarket has done on the stock.