If i join a yahoo group, is my personal information still hidden i.e. my email address etc?

i am thinking of joining the anti troll movement but not sure how it effects yahoo. users.
If i join a yahoo group, is my personal information still hidden i.e. my email address etc?
depends on the group- but when you post, any on individual mail will get your posts along with your e-mail address- consider using a web based e-mail like hotmail or gmail instead