I wouldn't like a FB format.FB doesn't have the same format. It is very hard to follow threads and the mail you get is astronomical.
As I understand it, the last exodus was only the latest. Before my time, as Kokonut pointed out, there had been other exoduses.
I think the reason the site was so active before is that we had a pretty much an even mount of opposing views. In fact, I think there were less middle of the road members at that time. When you get that type of population(no different than in our government), you are going to get a lot of hot button issues due to opposing views.
To the site's credit, there are a lot of new members since that time.