It's to help you discover people to follow.
There is deliberately no algorithm on here, so most of the discovery happens through human-run things like word of mouth, by following people who share posts by other people, groups, hashtag following, curator accounts and directories like this.
I posted this today because someone had sent me a message asking for lists to help a particular group find each other. If they join a service like this, that will be easier.
@credo @dansup @pixelfed
If you want more ways to discover people on here have a look at https://fedi.tips/how-do-i-find-accounts-to-follow-on-mastodon-and-the-fediverse-how-do-i-find-my-friends/