One criticism I have is not so much about the concept but the signup page. On your signup page you have that mini f.a.q. I think around a couple of those questions sound like they're coming from a skeptic. Your signup page shouldn't focus at all on the negative and I would probably even move the faq to a different screen all together. That screen is about funneling people into the service, not answering their questions.
Questions I think you can get rid of:
"Why isn't StorageRoom free?" -I have to pay for it, so should you, Jerk. The world isn't free.
"How does the 30 Day trial work?" - It's a 30 trial. You don't have to pay till you've been using it for a month. Haven't you ever seen an infomercial? Are you even smart enough to write code?
"What browsers work with StorageRoom?" - StorageRoom is a modern web app and, if you're planning on giving me money, you should trust that I put the time in to test on more than one browser. This isn't 1996 anymore you can't get away with "Optimized for Netscape Navigator 2.5 and later on and 800x600 resolution"... c'mon, seriously?
"Do I get a 30 day free trial if I upgrade?" - No, you cheap bastard! You already know what the service is like. You don't need to figure out if you like it or not. If you decide you need to increase your capabilities, that's on you.
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Sorry for the snark (well, not really... well, maybe a little.) You shouldn't be trying to argue an imaginary skeptic. You should be trying to tell us why your awesome product is so awesome.
Good luck!