The other annoyance: Unwanted messages, usually commercial or scams

First recorded spam message sent in 1978 "from a DEC marketing rep to every Arpanet address on the west coast"

Later mainly on the USENET groups, before moving back to email

Counter measures such as mass cancelling eg Arnt Gulbrandsen's "cancelbot" were effective

Growing number of email users attracted spammers to email again in late 1990s

Spam messages may very well carry malware