Thank you! The Activity Feed only seems to sort by date, when I was looking more for a "what's popular" view. But I found what I was looking for in the FAQ you linked to: the "My Tribes" option on the Front Page does exactly what I want.

Thanks also for the link to the index! That's really helpful. I'll be sure to flip through people's profiles as well.

/t/All seems to be a tribe, actually.

Thanks for the pointer to /t/newtribes.