I think if @Gargron wants people to adopt other instances, the onboarding process on joinmastodon.org needs a LOT more guidance beyond "here's a list of servers, good luck". Especially play up the shared-interest communities that instances can provide. Ask what people are into:
Make art? mastodon.art
Well-moderated community? awoo.space
Furry? Holy shit take your pick.
@Gargron Also, I know the instance list has a topic line, but that's not searchable.
@timotimo Honestly, I don't think instances.social is that much more helpful for a layperson newcomer than the one on joinmastodon.org. You can't search by instance description for a community you might be interested in, and there's no way to filter out things like instances that are down or closed for registrations on the "Advanced" search page.
Follow friends and discover new ones. Publish anything you want: links, pictures, text, video. This server is run by the main developers of the Mastodon project. Everyone is welcome as long as you follow our code of conduct!