Yea, I really like your Discord bots. Both Meaty's Wormhole and The Underground channel have been places to bring together BBS people
outside of the textmode world... I've been advertising The Underground Discord, and bringing my new users there. Its a good companion to the
BBS, and fills in some spots where BBSes lack 'current tech'. 
I too have found Discord to be of value for quickly sharing code, helping new  SysOps, or asking for help from SME's that I have limited knowledge within.  I  also love the collaboration when working on current projects with an RCS mod,  or two ANSI artists trading feedback, etc. And yes, the occasional funny video  post from ML are a great break during this "new normal" that is filled with  abnormalities. 
Discord is also a great way to archive helpful youtube links relating to tech,  coding, art, gaming, music, and good binge suggetions.  IN addition an archive  of helpful tutorials for newer sysops (such as ML's and BP's Linux Tutorials,)  MPL Tutorials, etc. Discord also is a fun place to show off new BBS features as 
there are SysOps who tend to call only when they here or get the vibe that new  things are to be seen (which is totally fine).   Most importantly, as you  mentioned Paulie, I find Discord to be a great intersection between the various 
avenues of Retro communities that otherwise would not cross paths.  
With the aforementioned said, I have to be careful not to allow the  subconscious to turn my server into another Facebook. I've been trying to  restrict my use of it, tie my hands if you will, to prevent that from  occurring, and just allow the community to use it as they please.  Discord can  have that similar psychological impact of "getting likes and new friends,"  etc.. if I personally am not careful.
My overall personal conflict with "Marketing" The Underground, besides my  dislike of social media, is that frequency to me feels disingenuous and or self 
promoting if done within every aspect of my communication. ML has a great point 
about the frequency on the BOT channels, and non privacy violating  websites/forums being a great place to strategically advertise, if done so with 
diverse content.  Paulie has done a great job of such on Reddit, as I get these 
magical users calling The Underground and/or signing up for the discord  channel, stating they saw "my" ad? lol!  Thanks Paulie, shucks.
As for what I've been doing to grow a user base at the Underground?  I suppose  a bit limited compared to some, and/or more organic approach by building  relationships with those who want to .. however here's what I have been up to:
1. Offering my help to other sysops, being receptive to feedback and making  changes to the BBS, and constantly working on it to improve the user  experience. 
2. Creating a 4:3 and 16:9 theme for those "old" and "new" to BBS'ing, offering 
diversity in preference. Behind the scenes building a third BBS. I may even add 
an Underground theme that is non light bar and more hot key/a decade more retro 
then either of the two themes I have.
3. Constantly coding and adding new things, drawing and adding new ANSI's, to  keep the BBS fresh trying to never give the feel of it being on idle. In  addition, being a part of RCS and writing mods that others like, with us  releasing new stuff with frequency, helps improve calls for support and/or to  see what we are working toward releasing next (if we do a good job and our mods 
are used ..)   
4. Content content content. I've been on several BBS's that look amazing, until 
one hits the main menu, and there isn't anything to DO. Like you, lately I've  been working to build my file area with unique content, and A LOT of it (as you 
know, but ... still only halfway there).  I think over 20,000 new retro roms  and more. Heck I have 11,000 C64 games online now. 
5. The Underground Discord Server that currently Quantum Wormhole, 20forbeers,  and Pimp BBS are utilizing; more are welcome to.  It's for all. 
6. Bot posts, but need to update those and apply more of the suggestions you  gave ML; and Paulie, I can help with the file formatting. The ANSI file can be  saved to Mystic posting requirements using the Mystic Editor, and Moebius makes 
it easier to set specific canvas requirements the post ansi file requires.   Also, I think I know two people reading or writing this post who are quite  capable of adjusting an ANSI to fit within the requirements ;)
7.  The Hitman game/mod, and working to dial it in from an appearance and  desirability factor, so that it becomes a more used and fun feature of the  Underground.  It slowly evolves daily, somewhere on the BBS :/
What I'd like to do more of:
1.  Trying to learn and remember to use Reddit, although, I haven't had the  mental capacity to "play in the forums or echos" until recent, hence the long  winded post. 
2.  I'd like to make video ads, but I'm unclear on the software to use for  Windows, nor where to get the software.  I remember when downloads.com was THE  place to see the top reviewed titles, of truly shareware and reliable software  -- I have found lately it is moreso malware and or free trial trickery.  Any  suggestions, I'll give it a shot! 
3. I'd like to start a video channel, but oddly not for retro computing.  Keeping it short, but can expand for those who would like to hear more, I'd  like to start "how to" videos relating to landscaping, lawn care, and plant  care beginning with very simple topics such as "how to properly use a shovel"  with my 4 year old demonstrating, as I can't tell you how many times I had to  prevent injuries of my past employees from not knowing how to dig correctly.  With the season approaching, I'd like to have the right camera, software, and  editing tools soon, to timely post decent videos online, preferably avoiding  youtube. And yes, somehow having my BBS advertising make sense within them  somewhere. 4. I need to get to a stopping point on 4 different mystic mods I'm  involved in, to temporarily shift my focus on getting my webpage on the .. umm  .. web.
5.  Basically, I have too much going on, must be my ADHD in overdrive.
Great conversation starter Paulie and ML.  These ideas, energy, and passion,  are what make or break BBS'ing.  I know there are many that feel BBS's are  nothing more then museums of the past; however I'm finding many new users  utilizing them in the present as a replacement of the toxicity of Social Media. 
Whether a BBS truly is nothing more then a relic, I refuse to allow myself to  have that mindset, as it only takes a few good coders and artists to really  show people that there is relevance to BBS'ing in 2021.  The more that are  helping peeps find both BBS's and Discord, the easier the efforts become --  both of you are much appreciated by many and I for your continued efforts.
-tG
--- Mystic BBS v1.12 A47 2021/02/12 (Windows/32)
 * Origin: The Underground [@] www.theunderground.us:10023 (1337:3/132)