JoeF, I think both systems have their advantages. I like the ability to quote and threading can certainly be useful where sub-topics crop up - with this system it is more likely IMO for a thread to wander completely off topic and never return.

The downside with the threaded systems seems to be that it doesn't take too "sub threads" before things start dissapearing way off to the right of the screen.

I did once ask whether the choice of threaded or linear formats did have any impact on the feel of the forum as I felt the threaded one is likely to encorage shorter to the point answers to points raised and the linear one was more likely to encourage more of a sort of free for all type conversation but I can't remember anyone voicing an opinion on this.

Jon