Not as much as people here would lead you to believe. It was one guy with the tips. Not the collective OT as many like to act.
Technically, people on the OT knew about the killer 2 weeks before everyone else. Things were lining up so spookily that people were telling Adam to edit his posts.
I think it even came to the point where the killer was on a rig and people were worried he would hear about this through the grapevine bc TD is so big and bolt outta town.