Likely true. Thing is, is LinkedIn (LNKD) worth $93 (where it stands right now)? Let me put it in perspective for you: it's price to earnings ratio (PE or the stick price * total shares / what you earned) is 561. The company earned $16M last year. The valuation has it at over $8.9B. Yahoo has those earnings even lower, putting the P/E at 1412.
Other prominent companies' P/E ratios:
AAPL - Apple - 15.95
GSK - GlaxoSmithKline - 37.48
Other brand new IPOs' P/E ratios:
WIFI - Boingo Wireless - 19.68 (Nice ticker symbol btw)
GNC - GNC Stores - 21.55
(ZIP - ZipCar had an IPO, but has not yet reported any earnings so P/E is not available.)