Off topic but I like your app and it looks to me like you can be loosing significant amount of first time visitors (How big is your bounce rate on homepage?) so I'll write it anyway.
Try some A/B testing with copy and amount of info (3 main blocks instead of 6... write not about what app does, but about what I don't need to do if I use it and so on). Now I see that it's something nice, well made and can be useful but it takes effort to actually understand it while it should be obvious.
It's hard to describe. I just think that this is a bigger problem because of conversion. (I'm a UX designer :))
It's all just scientific poking :) but I'd try for example to address the audience instead of describing app it self. Now you have "Twitter Machine - tool packed with features" so maybe just "tool for Twitter stars" or something like it would work better. What you should understand is that you are basically trying to get people to pay for using Twitter :) so you have to be talking with hardcore users and providing some solid arguments.
Try some A/B testing with copy and amount of info (3 main blocks instead of 6... write not about what app does, but about what I don't need to do if I use it and so on). Now I see that it's something nice, well made and can be useful but it takes effort to actually understand it while it should be obvious.
It's hard to describe. I just think that this is a bigger problem because of conversion. (I'm a UX designer :))