I'll offer some feedback right now... I think the product is pretty slick, but your site suggests this is the "easiest" way to send a file. A big question remains on what the first-time setup is like. How do I get other people on my "list" and how much friction does that process have? Because if it's any harder than right-clicking a file, selecting "Send via Email" and typing an email address, I'm immediately out.

Maybe other people could be asking this same question (and leaving your page before dropping off their email addy)?