ok i'll try to fulfill your legal concerns as far as i can.....
PM'ing a thread is perfectly legal and a common occurence in the world of the internet..... this is cited in the case of Jimbob vs. BillyJoe where Jimbob was upset that BillyJoe had pm'd him a thread regarding increased retardation within inbred families.... you see BillyJoe is Jimbob's son AND brother.... (i'll let you work that out on your own)....
now as for threading a pm it's still a touchy subject.... it all depends on whether or not there's been any penetration.... also it depends on the age of the pm..... your best bet is to just stay away from threading the pm's and stick to pm'ing threads.... much safer and keeps the ambulance chasing grey area prosecutors from hunting you down....
if this information has helped you and you have further questions visit me at....
http://www.icantbelieveijusttypedthisbullshitout.com