Viruses began their foray into personal computers 20 years ago. They initially started out by propagating themselves via boot sectors on floppy disks. Today they're all grown up and of course much more dangerous. F-Secure writes a little bit about the progressive malice in their News from the Lab blog and in a press release.
I still remember the days of trading 5 1/4" floppies full of software, not to mention logging on to BBS systems all over the world. I even remember the excitement of the first BBS to offer file downloads -- that was an event that definitely made headlines, at least in some places. It happened well before the IBM PC was even invented, and in those days 300bps was the standard for modem speeds. Blazingly fast compared to 115bps! LOL! We sure have come a long way since then.