In the mid-to-late 1980s, data was most often transferred from computer to computer by using floppy disks and so-called bulletin board systems (BBSs), managed online locations that were the forerunners of today’s Web sites.
Stowing away on floppy disks
Even without using the Internet, people in offices where PCs were used traded and circulated programs, documents, and spreadsheets — not to mention jokes, games, filthy pictures, and so forth. The standard method was sneakernet — walking up to another person and handing over a floppy disk.
In those early days, viruses spread relatively quickly. Because few people had antivirus programs, there was little to stop a virus from spreading from computer to computer. Like hobos on trains and stowaways on ships, viruses were unwelcome — and mostly unnoticed — passengers that rode for free and left their mark in some way.
Sneaking in via BBSs
Before the World Wide Web, BBSs were the precursors to the way we use the Internet these days. Reached via dial-up modems, BBSs contained a variety of features such as limited e-mail (you could only send messages to other users of that particular BBS), file uploading and downloading, games, and well, bulletin boards (where you could stick any messages you wanted seen by other BBS users), and so forth.