Mirth A-M died in 2009/10.
Not sure how public this was, but software was malfunctioning and most mods lost the ability to ban users and to promote (or demote) people from The Lobby. Only one admin - who rarely logged on - had the power to reliably do these things. The backlogs to promote and/demote users were enormous.
The forum became an unmoderated mess, very unfair in the treatment of its members, and many of us just quit in protest. I returned a year later to check on things and found it deserted. AnthonyG, who was making a huge effort to save what was left of A-M, told me about the exodus to here.
After A-M was sold I assume mods might have regained some of their powers, but the layout and ads made it completely unusable.