In particular, this is in reference to the field F_USERLIST. I don't know if it is supposed to be a default field or if it was supposed to be added by a mod that was released at one time ( if this is the case please move to the Mod Help forum ).
I am just curious as to what this field is, and how/where/why it's used.
Before it used to store all the member-id's of the members that were allowed access to a forum (in case of a Memberlist Only forum). Since that didn't allow for very many users (because of the limited fieldlength), we switched to using FORUM_ALLOWED_MEMBERS
You can find the code that converts the use of the one to the other in setup.asp if you are interested. To be safe we decided to not have the upgradescript delete the field after conversion, but left it were it was. It also made it possible to use the database in combination with older versions of the forum.