Amazon's interface really is pretty good, but unfortunately it doesn't allow reviewing stuff for which there isn't physical media (i.e. games which are only available online, such as Minecraft, or free games, like much of the Interactive Fiction scene).

This kind of contradicts my original reason for needing to keep an online review tracker, but it's significant: I need to be able to think of this as a (at least potentially) thorough log of experiences in a given media, or I don't think it will satisfy my magpie instincts.