Thinking about telnet & social media, I do remember that brief moment in time when the majority of my college's students had internet access but the web hadn't been invented yet. Telnet (along with talk, finger .plan's, newsgroups) had its moment in the sun. Enough so that I had a professor who would joke with us about getting our papers done before we'd hit telnet.

And thinking about MUDs, there is no better / worse way to feel the crush of time than finding your old MUD is still online. I found mine again a few years ago. Couldn't remember my password so made a new char. Used "finger" to look at my main. Last logged in 9000+ days ago. Looked up my friends who I used to spend hours with. Around the same. 9000+ days. Seeing it quantified in days rather than years made it more difficult and more personal. 9,000 days just gone like that.