It's not pissing in his letter box!

It's the private message service of the forum also known as PM
I've just sent you one as a sample.
To send a PM to someone, look below their avatar and click upon their username (in this case pscan,uk), you will go to the t-bar profile of the member
now look for a little envelope icon up towards the upper right hand side of the page, click on it and go about your private messaging business.