The recently released Backrooms movie is set in the old timey year of 1990. Some fun things were used to promote the movie. For example, this TV commercial was released (apparently shown on the Pluto TV streaming service):
In the ads a 408 area code telephone number. Calling that number got you to a fax machine, so folks figured out they could connect using FAX protocol and it would fax back a flyer.
There was also a Bulletin Board System (BBS) set up! Sorta. Since the days of dialup BBSes are long gone, a web site acting as a BBS Archive went live This allowed you to register for an account with the BBS and, once approved, log in via the website. You could then explore this BBS as it existed in 1990:
There were messages to read, and even the real Terms of Service which took AGES to scroll through at the simulated 2400 baud rate.

…and I actually scrolled through every page and captured screen shots.
There were also some files that could be downloaded:
ENTER.TXT
https://enter.backrooms.mov
ACCESS.TXT
=================================================
*** EXCLUSIVE OFFER -- LIMITED TIME ***
=================================================
Purchase your BACKROOMS ticket early at:
https://backrooms.mov
Advance buyers receive EXCLUSIVE ACCESS to
a local 408 business hat, available only
through this offer.
=================================================
SIZE.TXT
https://shop.a24films.com/products/backrooms-wallpaper
But how good of a BBS is it? I have thoughts. And, I actually starting using BBSes before I even had my own computer back around 1982. A classmate taught me about them, and we’d go down to a local Radio Shack and they’d let us use their TRS-80 Model 3s to dial in to Houston BBSes. Great times!
Nitpicking the Backrooms BBS
So … how good of a BBS would this have been in 1990? Let’s see…
No 40 column option
It is unsurprising that a BBS from 1990 would be using 80 columns. While there were still plenty of non-PC users (Commodore, Radio Shack, Apple, etc.) calling into BBSes back then, there were plenty of systems that natively displayed 80 columns (Atari ST, Commodore Amiga, and even later 8-bit systems like the Commodore 128 and Tandy Color Computer 3 all had 80 column displays). There were certainly plenty of 80 column only systems by that point, but most flexible BBS software still would let you set your screen width.
Use of PC-Only character set
What makes this look like a PC was the use of the “enter” symbol (a down then left arrow) found on IBM-PC keyboards of the day. I do not recall ever seeing that on any BBS screens I had visited. Was this common on PC-BOARD or some other MS-DOS BBS system? It was created using a left arrow and a “down and to the left” text character block, so it could have existed on a real PC BBS of the day.
https://en.wikipedia.org/wiki/Code_page_437
BUT, only the PCs with that character set could have seen this. It would have been some other type of characters for non-PCs. Only some PC emulating terminal program could have displayed it on a Commodore or such. On the CoCo 3, the only one that likely would have worked would be Twilight Terminal by SockMaster, which simulated ANSI colors and IMB PC character sets, and maybe NetMate by Roger Taylor. I am unsure if either of these would have been available in 1990.
But I digress. My point is, I would have expected a BBS in the heart of Silicon Valley to have supported more than just PCs in 1990.
Use of e-mail address for an account
Obviously, a BBS back in 1990 would not have used an e-mail address for an account. Most would let you enter your real name (or an alias), and a password, and perhaps a phone number. Some BBS SysOps (system operators) would call you up to make sure you were real before verifying your account.
But wait, it’s Unix!
The website shows a command prompt:

The “cu” utility is a Unix command (“call unix”) for serial connections. This implies the website is some kind of Unix machine and is dialing a number that is still in service. It is a neat simulation, but not something most of the BBS users in 1990 would have ever used unless they were at a university or some corporation with Unix systems that had modems.
And yes, I did try to alter the command line and change the baud rate. It did not allow it.

Content is key…
And, of course, the main thing is that there was only a handful of messages ;-) Whatever this system was in 1990, it was barely being used by anyone ;-)
Just repeat to yourself: it’s just a show!
But hey, it was a cool promotion, even if it wasn’t likely a BBS any of us would have wanted to use (or even been able to, if we were non-PC users).
For further reading…
Here is a website listing the various things that were done to promote the film:
https://kane-pixels-backrooms.fandom.com/wiki/Backrooms_(film)/ARG_Marketing
