You can.
Just click on my user name above my avatar, then click on "Show the last posts of this person" (bottom of the page, under "Additional Information")
ok, find Teufl for me and send him a PM.
he posts rarely, and usually in 300 post threads. I just talked to him in-game, and yet I can't find a recent post by him unless I scroll through 2 giant threads.
in the past I could just search user "xxx" and find most recent posts, then viola, PM available. find easily the last post by HiTech, Pyro, Natedog, or any other casual poster on the forum that reads a lot but posts rarely.