I'm old enough to remember seeing this exact image when it was new.
Seeing it come around on Tumblr as a joke about $CURRENT_YEAR is bringing up a... complicated mix of emotions.
(one of these emotions is "wow, now that I know what the Memphis Design Movement is, I see its influence everywhere")
Mastodon is a non-corporate alternative to a social network like Twitter. It consists of a federation of independently run servers which can exchange information with each other. This server, introverts.social, is meant to be a small and low-key one, intended mostly for people who are already my friends in real life. Sign-ups are by admin approval only.