In the 1990's back when high speed internet was not available most people relied on dial up networking in order to connect to each other or the internet. This utilized your phone line much like fax machines today do. A person would host a bulletin board system which basically provided a way for people to connect to this same bulletin board system simultaneously. Each person had an email box they could use and people also transferred files to one another. There was a chat room along with games that only contained text and no graphics whatsoever. Here is an example of what the main menu looked like on a BBS (bulletin board system).
One of these text based games that I played on a BBS was called majormud.
MUD stands for multi-user-dungeon which essentially means there is 1 land with all players on it at the same time. It was the dungeons and dragons board game on a computer with other players local to your area code. Dialing outside of your area code usually meant that it cost x amount of money per minute. As technology advanced, World of Warcraft, the graphical version of majormud, was created.
I've never once played world of warcraft but continue to play majormud to this day with other people around the world.