Let's not forget they've taken nearly $100M of investment at a nearly billion dollar valuation. Perhaps this is my east coast conservatism, but in the average case I just can't see how this works out well for the investors.
To get a respectable exit of perhaps $4B in a few years they would have to get their revenue up to something closer to $200M/year assuming you gave them a generous valuation on 20x revenue and completely neglect profitability. Given that Evernote primarily makes money from paid users they will need to dramatically improve conversion, or somehow figure how to get 10x more users. 200 million users strikes me as unlikely, and doubling conversion while also getting 100 million users does too. It's not to say it can't happen, but I just don't see it for a paid consumer service.