Once upon a time, roughly thirty years ago, there was a computer network called America Online.
AOL, as it was typically referred to, sent out little diskettes[1] in the mail, and sometimes slipped them into the middle of popular magazines. The diskettes were a way for people to go online. There was already an Internet, but most people didn't know how to use it or even that it existed.
AOL, and a couple of competitors, Compuserve and Prodigy, offered people online things they could do, such as chat with other people. Mostly, the services helped people to get around the difficult aspects of what are known as Internet protocols. Internet computers need to communicate via connections that require a dedicated communications line, and a so-called IP address, which in turn requires a software program called TCP/IP. Most people's computers didn't have any of that.
Instead, the little diskette in the magazine let a person plug their computer into their telephone modem — once they'd bought a modem at the local computer store — and dial up a server computer that would admit them to the world of AOL or, alternatively, to the world of Compuserve or Prodigy. Some people grumbled at how many diskettes were stuck inside magazines, but the diskettes were an effective way to attract new people to sign up and use the service.
Many people spent days and days at a time on AOL and the other services. The services had only one drawback, which was that they were limited. People couldn't do just whatever they wanted, they could only pick from a small menu of functions, such as chat, that the services provided. And the services didn't grow or change much, they stayed pretty much the same for years