I don't think ratings is just the number of stars, but also the number of people who have the channel installed who selected those stars, and may also include the number of active users of those channels vs inactive i.e. has the channel been launched in the past 7 days.
Also, the web store uses a different algorithm from the Device Channel Store, and my comment about BradC's channels was specifically about the device store. The web store, well... there is a new release of the Web Channel Store going out some time tomorrow, so let us know if it improves this situation or not. I'll also point the web team to this thread.
- Joel