Interesting idea.

The scoring system could get complicated. What about people who charge round trying to be helpful all the time but consistently get it wrong.

And you get heavy irony of the form "Oh what a very sensible thing so-and-so just said" - and someone somewhere has got to decide who started the subsequent mayhem. In fact with an international membership dealing with things like irony could be an insuperable hurdle.

I think that the people who go on about cliques and gangs and so forth would freak at this sort of thing. Which might be a reason in itself for introducing it.

Perhaps a modification might be that any thread started by a GUEST would show up in a different colour. (And I now there are some very good GUESTS who have the courtesy to add some kind of handle, but who for various reasons don't want a cookie - but the percentage of trolling threads started by GUESTS is high enough to merit a warning of some kind.