I've avoided signing up because I couldn't find a price.
Just saying its free / there is no pricing plans yet etc would have let me sign up, or an actual pricing list.
I won't try a service without knowing whether I can actually use it going forward (I'm time poor) so the lack of pricing information anywhere makes me leave the page.
I had the same question as @jd - to clarify this, you might want to change the call to action to "get started for free" or something along those lines...
That implies free forever, you want to commit to that? That's also what it says now when I first viewed that and yet I still went hunting for pricing. I would actually trust signing up for the free account more if I saw there was a paid option somewhere for whatever reason!