I went to check out the capture a photographer thread today and recieved the message that the server was too busy. I checked how many people were online 5 in that thread and 144 in total. I wouldn't have thought that would be enough traffic to cause the server to jam up. Perhaps we were doing maintenance at the time as I guess I am logging in during what would be the wee hours of the night in the US, but if not then It is probably something worth keeping track of.
incidentally I clicked back and clicked into the thread again and got through straight away.