Boogie, people admit to criminal activity on here all the time. At what point would you take action?
A combination of the seriousness of the offence, and the amount of detail I could gather/provide to US authorities.
But people talking about their own personal drug use on here simply isn't worth it.
Regarding our friend Thor, I have been tempted, if only to offer up a "hey, is this guy on your radar, or is he just crazy?"
as a sidebar, a while back, some coworkers did knock on the door of someone who had threatened to kill a US official on a prominent internet forum, at the request of US authorities. Turns out the guy had mental issues. But still, it shows that law enforcement is willing to take "lol, internet forums" shit seriously, and even pass along such info across borders.