When the new forum was coming online, it was announced that no user information would migrate to the new forum. They would have to log in, and create a new account. If they were from the old forum, we bumped their user level up. Some signed up under new names. many didn’t migrate. We have also had a bunch lately fall on their sword (happened then, happens now).
Some found a new home and slowly moved away from here.
Veriety of reasons that some of the old timers are not here anymore.