I'm a new user (long time lurker). I've noticed when I join a new main site to my account, I get a separate set of badges for that main site.
Does rep behave the same way or is it propagated between all my main sites?
Does rep behave the same way or is it propagated between all my main sites?
Yes, rep behaves the same way; no, it doesn't propagate between main sites.
What does happen is the association bonus - when you reach +200 rep on one main site, you get a +100 rep bonus on all main sites.
See: