It's true that I am trying to do a lot by porting Mockups to multiple Web Office platforms, but the revenue potential is very clear if I market my products that way (a lot more clear than doing a hosted solution, at least in my mind). And as a one-person, bootstrapped company, I have to go where I see revenue first.
As for your use-case, I think it's a definitely important one, and that's why I offer Export to PNG and export to XML even in the free web version. I believe a non-technical client could take a stab at creating a Mockup, export it and send it to the designer/developer without too much effort. Sure having a twitpic or skitch-like page for commenting would be nice...I just don't have the bandwidth for it...yet. :)
As for your use-case, I think it's a definitely important one, and that's why I offer Export to PNG and export to XML even in the free web version. I believe a non-technical client could take a stab at creating a Mockup, export it and send it to the designer/developer without too much effort. Sure having a twitpic or skitch-like page for commenting would be nice...I just don't have the bandwidth for it...yet. :)