mastodon.social is one of the many independent Mastodon servers you can use to participate in the fediverse.
The original server operated by the Mastodon gGmbH non-profit

Administered by:

Server stats:

366K
active users

After levelling off for a few months, it looks like Mastodon's MAU is climbing upwards again. From 1.15M at the beginning of April to 1.21M today.