I've started up the Drumstodon.net Fediverese instance (running on Mastodon) in the end of November 2022 during the second big migration wave from the birdsite.
Exactly it was on 26th November 2022 when I procured the first server and installed all the needed services. On 27th of November the instance has been online and open for sign ups.
The motivation behind all of this could mainly be split into the following points:
The start has been pretty slow - I shared the news about the instance from my other account on the Fediverse and it slowly received a bit of boosts and nice comments. About 10 great and passionate people/drummers joined in the first week or so. For each of them it was just a second or third alter ego on the Fediverse, but that is fine. That's the beauty of free existence and right to choose. You can have many accounts and on each share only what you feel is appropriate for the given community...
Then shortly before Christmas on 18th of December 2022 the instance (although very new and with only about 11 active users reported) got approved and published on the joinmastodon.org instances list. This was big, because it was exactly during the next bigger wave of migration from the birdsite and the people started to join in! Up to 01.01.2023 the users count grew to ~250, although only a handful of the new accounts seem to be really active users, there are many lurkers who are returning time to time and even more "nickname" holders or seemingly abandoned accounts in that number.
I hope everyone who joins Drumstodon will in the end be happy and have a great experience. Let's hope it is achievable.