OK, I tried it. I am... not totally impressed. It is definitely an interesting application, with some useful and interesting features. But the interface is slow, clunky, and not very responsive or well thought-out. The data retention and "sharing" (with the developer) policy is not great IMO. The app has a system tray icon *and* a persistent taskbar icon, which seems pretty unnecessary. And the "history" function (automatic capture of your browsing history) while promising, is implemented very poorly (and yes, I know what you're thinking, don't browsers already have history?). I could go into detail but bottom line is I wouldn't recommend it at this time.
I *do* like the idea, and the simple built-in tools for annotating your captures. A similar such tool with a better and more responsive UI, better organizing functionality (such as drag-and-drop to custom folder names, and/or tagging of captures), and no data mining would definitely be appealing to me.