Walmart's P/S is low because their operating margins are so low, and Walmart's P/E is actually almost the same as Google's, because valuation is a function of c

Walmart's P/S is low because their operating margins are so low, and Walmart's P/E is actually almost the same as Google's, because valuation is a function of cash flow, not sales. What kind of addressable market do you see for Evernote, and what sort of margins do you see them making over the long term? I just don't see an online note taking app being so difficult to reproduce, so I don't know if they have pricing power to generate the cash necessary to support a $1B valuation. Particular after you consider execution risk, and then leaving room for this round of investors to make an attractive return.