that's a good question @gillianpearce... I know they list all the trails and how many people are following them. I think you can go through them and figure out what their purpose is by either they're name, their blog page, or by simply messaging them. I know what we are doing, so if someone would ask me, I would definitely give them and answer.

btw you can follow 100 trails if you wanted to... I don't think there is a limit. ;)