i can see how this would be useful for requirement gathering or informal high level design, but if I cannot export it to a format which i can version control and/or access programatically it remains a toy.
now if i could have an open source version of it....
You may find Edit Room (my product) more useful then.
It's a visual web design application that lets you design all the way from rough wireframes to detailed, precise designs. Full export of semantic HTML, clean, usable CSS. Much more...
I just took a very quick at the demo's, that is really slick. I'm loving the pallettes and the UI in general.
Couple of minor things: the font that you use ('Sorts Mill Goudy') really isn't that clear or crisp, simply falling back to the default browser font looks much better. Secondly, I'm not a big fan of your menu - it's very sparse and blends away too easily (the one in the top right) and IMO 'features' link should be more prominent and at the top of the page.
now if i could have an open source version of it....