There's nothing stopping a server admin from allowing marketers to buy accounts or ads.
Money seeps into and corrupts everything and it will happen here too.
Not that vigilance wont be useful. Not that the ability to switch servers won't be useful.
@BernieWonIowa @anildash Still a hashtags can't trend on other servers unless it's not approved by their server admin.
What trends on our server are decided by our admin and moderators and it doesn't matter where it's coming from and how popular it is, we look into the trend individually before accepting it.
So from my understanding, what you are saying is only applicable for individual servers, not the fediverse