People know what twitter is. They may not know that it is "microblogging" but know it is a social network.
Mastodon has been mentioned in the mainstream tech (20k foot view I call it) long enough that even somewhat techy people know what it is (a social network alternative to twitter), but may not have any idea what activitypub or fediverse means.
This is not Craig's mastodon instance. Fuck Twitter.