During the early 2000s, the dot-com bubble coincided with a telco bubble, with everybody working themselves into a lather over the promise of WAP, basically dial-up modems for mobile phones: slow, underpowered, charged per minute and thus hugely expensive. Working at a telco operator, I had access to the logs of the WAP gateways serving up the stuff, and far and away the top use was porn, with waperotica.com being particularly dominant.
The catch: this was way before smartphones. The Nokia 3310, a typical device at the time, had a 84x84 black and white (really more black and olive) display, considerably worse than the CP/M 256×192 panned in the article -- and still people watched porn on it.
Intentional or not, WAP (Wiresless Application Protocol) was a real protocol that allowed you to surf the web on a cellphone in the late 90s/early 20s, before 3G was a thing. Most websites (or wapsites) were super barebones and relatively fast for me, and you could find interesting stuff like cracked .jars of popular games or of course, porn. https://en.wikipedia.org/wiki/Wireless_Application_Protocol
They had to be barebones. WAP only supported text and tiny black and white (no greyscale) images. I did some WAP sites and it was pretty horrible to work with even back then. The phone I used (Nokia 7110) didn't even support GPRS so you had to make a call at 9600 baud and pay per minute so you didn't want to hang around either.
The Japanese had i.mode which was much more powerful. They tried to introduce it in Europe but by then the smartphone was already coming.
Why are people using euphemisms here? The sexual reference: WAP stands for "wet ass pussy", popularized by Cardi B: https://www.youtube.com/watch?v=hsm4poTWjMs. The music video has over 400M views.
The term (as a word, not an acronym) is also used to refer to self-indulgence, generally among males. That and earlier references suggesting various modes of beat being laid down are what I was referencing with my etymology link above.
"Fap" began as onomatopoeia popularized by the Sexy Losers webcomic, first appearing in https://www.sexylosers.com/comic/003/ (NSFW in case that wasn't obvious).
There are sex-themed text adventures (e.g. Drive-In in which you're at a Drive-in movie theatre with a date: https://ifdb.org/viewgame?id=gksf13iptntcx5m6 ) but most of the people writing "amateur literotica" are middle-aged women and the pre-VGA era PC has far fewer of those proportionally.
In terms of more conventional erotic literature (not branching narrative) that takes off more with widespread access to the Internet because it connects writers and audience. Today authors can gently shade over, from giving away fan-fiction on AO3 to producing cheap Amazon e-Books that make you enough to buy a coffee once in a while, to getting paid professionally to churn out stories for an outfit like Harlequin that can afford actual editors (even if you read two Romances a day like my mother, the fact Jim got taller and grew a beard in the course of a single chapter jumps out, not to mention the fact his older brother's name changed, and so she can tell if she's reading a story that a professional gave the once over before it was published). The Internet also caused readers to explore more, instead of buying a box of a dozen Edwardian-era Romantic fiction novels at a time, knowing that's more of something you like, when it's one click away why not find out whether you're into werewolves, or gay relationships, or the Wild West, or whatever? If you hate it you can click away and be reading yet more stories from the early 20th century British Empire in seconds.
The catch: this was way before smartphones. The Nokia 3310, a typical device at the time, had a 84x84 black and white (really more black and olive) display, considerably worse than the CP/M 256×192 panned in the article -- and still people watched porn on it.