One-way multi-person video iChatting

Cool. We're all familiar with one-way video iChatting: If you have an iSight but your friend doesn't, you can still video chat with him — the catch, of course, is that while he can see you, you can (obviously) only hear him. What I
didn't know, though, is that you can have a multi-way video chat (2 or more people) and still invite into the conversation folks who don't have a webcam — you can hear them, and they can see and hear everyone else.

My friend just invited me into a chat — he and his friend were talking via iSights, and since my iSight is laying somewhere in Boogymansville under my bed, I was only present audibly — but I could still see both of them in iChat's neat multi-person video chat window. This leaves me asking: How many non-video participants can be involved in a multi-way video chat? Nine (minus the number of video-chatters)? Or are we limited to the video feature's four?