Ability to contact forum members direcetly

Often I would like to talk to some forum members about stuff directly. 

It would be nice if we had a message system where you could drop a line to a member asking if they would share contact information.

I now saw a huge problem on someones company site and am not able to contact him but don't want to share that information in the forum.

And I don't want to post a Dr. Mr X would you like to contact me.

Markus