You don't need to join the instance to see its directory.
When I started my own instance, I went to a handful of different instances and looked at the directory. Then I started following the ones that seemed interesting. That was enough for me to bootstrap my feed to the point of something useful.
When I started my own instance, I went to a handful of different instances and looked at the directory. Then I started following the ones that seemed interesting. That was enough for me to bootstrap my feed to the point of something useful.