I had forgotten about it until today where I had to place a message to another siteuser and making note of the seemingly unneeded steps.
First you have to click on their name to bring up their forum profile.
On the forum profile where it says you can contact the user, it ought to have a message link. Yet it requires you to click a second link to bring up their warcraft pets profile. Surely the two could be merged? Was looking around for a bit for a contact link until i realized there was a second profile where it was found on.
Here you finally get to the page where you can write them a message.