Back in the day, I devoted hours to those old forums, and not just to buzz around making noise, which is my chief contribution here. I used to help sift through dozens of RML threads a day, offering advice (really good advice too, if I do say so myself). I hunted bugs. I helped newbie lenders get their bearings. I did statistical analyses before we had a lot of fancy third party sites. I really devoted myself to Prosper for nearly a year, chiefly through the forums.
The forums started getting ugly around January 2007; when 2Millionaires started throwing their weight around. Prior to that, it was a relatively mellow board. There were flare-ups, usually pitting lenders against wackos. There were very few lender vs. lender arguments, and everyone seemed pretty pro-Prosper and genuinely rooting for its success (to the degree of being almost protective of it).
Two things happened:
1. A huge influx of new lenders swamped the ones who had already been there for a year. There were tons of reguyncali types who thought they knew everything, and ridiculed the seasoned lenders for having only four digits invested, and things like that. That was when the (always untrue) axiom got started that the most prolific posters had more posts than dollars invested. That caused friction that resulted in big flare-ups.
2. It slowly became evident to the older guard that Prosper was siding with 2Mils in the argument, which left many of them (including me) incredulous; we couldn't believe that Prosper was willing to wipe out its embryonic culture for the sake of a spamming, scamming butthead like 2Mils.
That's when the forums started directing anger at Prosper itself. On 3/30/07, when Prosper decided to trump up charges against a "little gang" list that might as well have been submitted by 2Mils by suspending them for honest posts they made in reply to 2Mils baiting back in December, there started the rift that never healed.
From that point forward the forums got worse and worse. Partly because the devoted lenders stopped devoting themselves to a forum where they felt their time (and money) was unappreciated. Partly because Prosper launched a series of lender-unfriendly actions over the course of the year, which deserved loud criticism.
They finally wiped out the forums. Yes, the forums are now a much "nicer" place to visit than in 2007 (but not necessarily nicer than in 2006, when there was almost no moderation). But only because they nuked them completely. Eventually, lenders on the new forums will get critical, posts won't go up, and you'll have a new crop of disaffected lenders, wanting to join this cesspool of negativity (only kidding), .org.
In short, what happened is Prosper threw a party in their house, whacked the guests over the head with a rolled up newpaper repeatedly, got shrill at the guests when they complained, and threw them out. Now they have a new party, new guests.
Don't blame the forumers for the state of Prosper's old forum, or .org Posters are reactionaries; they respond to what's thrown at them.