You seem to be getting a lot of technical and user oriented feedback, so I won't bother you with even more of this. From a marketing standpoint however, I feel

You seem to be getting a lot of technical and user oriented feedback, so I won't bother you with even more of this. From a marketing standpoint however, I feel I can provide some advice. The benefit of your service is the unique compromise between site design and monetization. The current solution (adsense et all) detracts from the design of the site and is an unfortunate compromise that site admins must make in order to be profitable. Your product gives me, and all prospective customers a beautiful site without ugly ads carved out of the site's design. Quite simply, we can have our cake and eat it too, or translated: we can have a beautiful site and still run ads. Most of the literature on your site refers to running ads in the "emtpy space" on a prospective user's site. It took me about 5-10 minutes to figure out the true value of the site, the "Hey! Now I know what this could do for me!" and I come from a more technical background. Other bloggers and site owners may barely have a working knowledge of their site, and to them, I would think that the message they would perceive is "Fill up all the empty space in your website!" which hides your true value. "Have your cake and eat it too!" - I think stressing this point in your site's literature will serve you much better than "Monetize your website's empty space"