I don't know why this reminded me of a really scumbag troll thing we would do on AIM/AOL. I guess because it involves sound and open/close.

If you remember using AOL or AIM(AOL Instant Messenger) there were sound effects for various "events" like "Welcome" or "You've got mail" when you got a new email.

AOL and AIM had "buddy lists" and there were sound effects when they came online or offline. Like a knocking sound and door closing sound.

In the early 2000s when cable and DSL was becoming more widespread, it became cool for people to leave their AOL/AIM accounts connected all the time. This generally meant a computer running usually in their house, bedroom, or living room. People would leave "Away Messages" sort of like a status on a social media timeline. I think Jack Dorsey said turning AIM away messages into a timeline was one of his original inspirations for making a social media app. Anyway

So someone opens Visual Basic and starts writing some code. It goes to the privacy preferences of their own account and checks "Don't allow anyone to see me online" and then clicks apply.

Now it checks "Allow everyone to see me online" and clicks apply.

What does this do for everyone on your buddy list?

They hear a constant rotation of WAV files like BuddyIn.wav BuddyOut.wav. Over and over.

you can hear in the first few seconds of this video https://www.youtube.com/watch?v=AQjfU4g6_SQ

Even farther off topic, but this reminds me of the time my friends and I recorded a 3 minute long wav file that ended with a quiet “this is god. Can you hear me? I’d like to talk with you,” and set it to be the error sound on a friend’s PC.

Much hilarity ensued.

Back in the late 90s, ICQ's "oh! oh!" (incoming message) has been used in media items (such as TV) about online threats such as malware, phishing, or just anything concerning children (such as online predators). One cool thing though was that there were entire sound packs to turn your ICQ into something else. And if you'd use it as ring-tone on your GSM (before that smartphone age) people around you would recognize it.

I guess I could still use it when my wife messages me on Signal.

That reminds me of the Hook Flash in telephony for getting an operator's attention: https://en.wikipedia.org/wiki/Hook_flash#History