There's an IRC channel for Altium Designer that myself a few other people hang out on. I access it through the freenode server. The channel is #AltiumDesigner. Yes, the sharp is part of the channel name so you have to join it with:
/join ##AltiumDesigner
There's also a general PCB IRC channel named #pcb (another mis-named channel with an extra sharp):
/join ##pcb
If you've never used IRC before there's plenty of tutorials on the web. One tip - don't expect immediately replies so stay logged in (many users leave their IRC clients open 24/7). Another tip - if replying to a specific individual publicly, start the message with their ID because most clients will beep or pop-up a notification whenever your ID is found in a new message.
On Windows you can use
mIRC. On Ubuntu Linux I use the Gnome version of XChat. There are
many more clients available.