Im not bothered about adverting your products as long as its not just advertising in every single post and theres a human element to the social posting Rule 5,6 of Cupoftea.social (my instance) "No accounts setup purely to sell something / Fake Engagement (Such As Investments/NFT/Cryptos/Wealth stuff) There has to be a human element in your posting. ""No spam , Excessive promotion , Porn or S**t Posting, Its just not for this server " Mastodon.social is full of crap and its user numbers are mostly from spam bots and porn.
Mastodon has 13 million.
Not sure where you got the stat for Fediverse as a whole on that.