My first reaction is that it is very fair. Sixty days is long enough to get a feel for the service and "hooked." The price seems definitely worth it. One problem I see with a trial period is that someone may sign up and start using it, but then stop after a few days. With this kind of service, a big obstacle is just getting into the habit of using it (as I'm pretty sure you're familiar with;) ). If someone wants to come back later, but their trial is up, they probably won't pick it up.
I'm no businessman, but what about having a free plan and pro plan? (And I'm not even saying that I would want that.) For example, the free plan could limit a user's ability to browse their timeline and methods of creating notes. And the plan could be a no-commitment month-to-month thing.