Looks nice and like a good idea, but according to the FAQ it's Windows only and there are currently no concrete plans to change that - maybe you should mention that somewhere in the introduction, e.g. "Ritt supercharges your Windows file management with the power of tag trees"? You might argue that Windows is still the dominant platform, but not so sure how true that is for your target audience (users who install a paid file manager). Of course, being cross-platform would be an additional selling point (people would be able to use the same file manager on several platforms).