The Internet in 1999 was comprised mostly of individual websites run by individual people. WYSIWYG website builders were new and exciting, allowing laypeople and ten year-olds to make sites without much technical expertise. People of similar interests found each other through webrings and message boards and chat rooms. Digital word-of-mouth was limited, and virality wasn’t possible.
I’ve had a personal website since this bygone era, and in those days, if people wanted to know when I updated with new art, they needed to go to the site manually and check. The Internet was small, so this wasn’t too arduous a task.
Nowadays, the Internet is pretty big.
It’s not practical to manually check lots of individual sites anymore. Besides, while most creators posting stuff online in 1999 had websites, this isn’t true of their 2019 brethren. Some might have both, but many artists now only have social media accounts. Social media is convenient. Not only do you not need any technical expertise, you don’t have to build anything at all. It’s much easier for people to find you, and they don’t have to manually check your feed every day. Everyone they follow is combined into one feed. So handy!