Evernote has high customer acquisition costs; there is only so much that virality can get you, on a paid product, even if you have a solid value prop.

See also: Wesabe founder's analysis of Mint's stall in traffic after they got acquired by Intuit (and stopped paying for customer acquisition)

However, see also: Max Levchin's comment at startup2startup that the reason PayPal and Slide raised a lot of money when they did was because they figured out that the environment was getting too frothy and about to crash.

Startups that can raise B (and more) right now, will, and should. The hundreds of startups that are raising Series A right this moment will be competing like dogs for follow-on money in 9 months - and guess who will be in power position then?