My only interaction with #SSB ( #Secure_ScuttleButt, not #Single_Sideband ) has been through #Manyverse, so take this with a grain of salt. That said, when I joined, you'd go to a list of "pubs" and copy an invitation code, so you could see and be seen by other people.

Now, they're using (usually limited topic) "rooms", and most of the pubs are gone. The public rooms list is small.

It makes it unattractive, because the only way for most people to participate is to host a room / pub server. As a result, I deleted Manyverse from my devices.