Actually, they've helped me in sort of a weird way. Before I came here, I would've thought it was nuts for anyone to wish their opponent not to resign...still less, that they would think they were being slimeballs for doing so! But having read these forums, I can see why a "less experienced" player would feel that way.
Improved chess understanding

There are a bunch of posters the last couple of years, that actually do teach things to me about chess. So I would say 2000.

Mostly it looks like there are people asking stupid questions, and then they get marauded by a roving group of jokesters who in my opinion rightfully smite the stupid questioner... So in some sense, I learned what not to do via lots of posts of people's 'invented openings and novelties' and things of that nature.
Sometimes when people post games you will see responsible stronger players giving contstructive criticism and feedback and that appears to be the most useful to me. I definitely had some good things pointed out to me the one time I got up the gumption to post one of my crappy games.
So I would say 1859.34 out of 2849. The articles have been a little more helpful in terms of gaining applicable knowledge. I would give those a 2456 out of 2849, but maybe those run on a different rating system? I'm no expert.

Of course, all of this is assuming that the only purpose for chess.com forums is to improve your chess understanding...
I'll be up over 3000 ELO once I decypher this:
Then you'll cure cancer and create world peace.

I have been trying to find a helpful reply by the blocking guy that will improve my chess understanding. Still searching.....

Have there been any developments in forum-involvement related improvements lately?
You mean in the last 3 years?
On a scale from 1 to 2849, how much have chess.com's forums improved your understanding of the game of chess, would you say?