A quick look at the front page (particularly the stuff focused at the very top) does not suggest anything so much as a competitor to Gmail. Scroll down and the feature list does little to change this impression. For $20/user/mo? All right, you don't have the resources to compete with Google... I understand... but how does that change my decision as a potential customer?
Maybe it would help to emphasize a little more on what the distinctive advantage is here. Is the point just to get out from under Google et al. with a similar product? If so, maybe find some way to invoke the problem you see with Google et al. I don't know what you MEAN by "innovation from the inside out" or why it matters to me enough to pay $20/user/mo (for the preview; it looks like you plan to increase the price later...)
Phrases like "shit work" and "dick around" and "sticky fingers" on the questions page might be phrased more professionally, and several pages could use punctuation work (you seem to omit periods a lot)...
I am a little concerned about a "custom mail engine I'm writing from scratch". Are there not any established tools to build on in the Ruby world? Why do I want an email service which does not support IMAP or Android? Is this primarily geared at Apple devices or what (if so, that could be signaled more clearly...)
Good luck