It sounds interesting, but you don't really say here (or on your website) how the system works. (The website is clearly in a rudimentary form, since all links to more information lead to the same page.)
I take it one uploads the DRM-free books of interest, and the actual book files are synced to different machines? Or is it just the placemarking info, etc., that's synced? It only works, I assume, with wifi-enabled devices? Is it cross-platform? Can an iPad sync with an Android tablet? And so on.
More info would be helpful.