Well, PMAC, I would estimate that first 18 months of that 3 year life-span was time spent waiting for a single reply to early threads, therefore I would say the forum was indeed a success.
That isn't to say there's no room for improvement, but the work amongst the committed (they know who they are) means that things are evolving all the time. Another measure of success, I suspect.
The all pervading apathy of the early days, or whatever you want to call it, means that the forum could easily have died IMO, so surely this must also rate it a success.
Look at it another way - there's no other UK forum dedicated to 240/260/280/Z31, is there? (I'm happy to be corrected here) I think 300zx.co.uk pre-dates us, and the 350 one was inevitable, so I think zclub.net does deserve to be celebrated.
Just my 2p.
JB.