A very important man here in the Detroit area for us BBSers. When Horst Mann logged onto your BBS you were excited because this meant you were going to be on the next 313 BBS list. I never understood how this guy managed to find the time to log onto every BBS in the Detroit area, let alone to pay for the exorbitant zone call charges that Ameritech charged (about 8-10 cents per minute, depending on the time).
When your BBS first appeared on the 313 BBS list, which was later renamed the SEMBBS - South East Michigan (Detroit area)- list when all our area codes got split into 734/313/810/etc, your BBS would be flooded with tons of people. And sometimes quite a few would stay.
And the new 313 BBS list was the hot property to upload/download on every BBS in existence. If you got an early copy, you were psyched because you had tons of extra upload credits on lots of different BBSs.
I never did figure out how he got his info on the new BBSs. I never did advertise mine anywhere where he would find it, but he found it nonetheless. "The Quest for the Holy Grail" made its appearance for quite some time. (And I never did find the BBSs that this Horst Mann fellow actually hung out at.) He would categorize your BBS by software (TAG BBS/Telegard/WWIV/etc), interests (Computers, Role-playing, etc), and location, and then add it into his list afterwards. (You could email him with corrections, if you were so inclined.) Eventually, he might call back just to check that you were still up for his next update.
The Lansing area had a system where you would call a single BBS and add your BBS name through some sort of door program, and that program would later confirm that your BBS existed and allowed logins. But, that was a whole lot less exciting than Horst Mann's methods.