I know there’s no good answer to the hashtag problem. If you’re running a very small instance, chances are you might get overwhelmed with too many posts if hashtags were federated more liberally. But on the other hand, you don’t actually know you’re missing out from a usability point of view if you search for a hashtag on your instance, especially if the instance is small. Like I don’t know about you, but to me that’s not great user experience. I bet a lot of people don’t know this happens and are confused as to why their favorite hashtags are so quiet, when they might not be.