Mildly reminds me how being online on AIM or ICQ was an actual invitation to chat. I had so many interesting conversations with people I barely knew. There's no source of that signal that someone is open to chitchat these days, and it's in my opinion kind of killed what was once great about online communication.
Huh, coming from an IRC and email background I have the opposite reaction. Rather than having to wait until someone is online it is much nicer to just type to them and they'll respond once they can. Everyone is open all the time!
I was in college during the peak of AIM and it was useful to know who was at their computer or not, which I believe was still viable. Around meal times, we could quickly scan for who was around to see if they wanted to head down to the cafeteria. If they weren’t around, there was no point it asking. For time sensitive messages, online status matters.