PM is a useful tool (VIP only). It is a great addition to reviews. I have been exchanging PMs with quite a few members here and it has been very helpful. Also, information I receive through PMs is quite accurate and so far, I have never been disappointed by the information I received thr PMs. However, its has Cons as well.

Pros:
PMs sometimes provide info that is not published in reviews.
Many great recommendations and tips. Often works better than the search engine.
Create small underground groups with similarly minded members to share experiences

Cons:
Kind of violation on privacy (poor providers)
Sometimes tell me I shared a provider with some members and I was #2/#3 that day - YUCK

Any others??