Woo! As you may have seen from that previous boost, Mastodon 2.9 is now out, featuring a new single column interface:
This is, IMHO, a huge step forward for getting non-technical people onto Mastodon 👍
Instead of the Tweetdeck-style interface, there's now a default single-column timeline which is much less scary.
(The multicolumn original is still an option in Settings, and those who currently use multicolumn will continue to see it by default.)