4. The mail man's call
The cry of the AOL mail man was damn near ubiquitous in the 90s. For future generations, it'll be about as familiar as those blasted "50 free hours" disks we used to get sent every seven days.
5. The Nokia boogie
It was the ringtone before there were ringtones -- the predecessor to an infinite array of annoying pocket-based serenades.
And here you thought your co-worker's Kanye song was bad.
6. The busy signal ballad
Between call-waiting and speech-based signals ("The number you are trying to reach is busy..."), the soothing sound of a busy phone is something you rarely hear these days. Unless it's sampled in a future Puff Daddy song, odds are, it'll be just another random tone to tomorrow's teens.
7. The dot matrix jam
Today's printers might actually work -- well, most of the time -- but boy, do they lack the vocal prowess of their predecessors. The bone-crunching sound of the dot matrix is one of the most immediately recognizable noises in yesterday's technology. What other sound, after all, so deafeningly conveys the message: "Hey, buddy: Get ready to fix a paper jam"?