My contact at the Eunach Archive has made the following point regarding their fiction library, which I include for fairness and completeness:

The VBulletin system makes a user database. The fiction archive for stories uses it. The 2 are not otherwise connected. Users of the fiction section will be purged after 365 days of not being logged in to VBulletin boards. That’s why so many readers get deleted. It’s a VB automation thing for purging inactive members.