I honestly think smaller more stable groups are going to yield stronger relationships than ones that are continuously growing.

I've been on reddit for ~12 years, for example, and after five or six years still hadn't really cultivated any kind of 'group' or relationship with anyone, so I just started rotating my accounts regularly because the social aspect of the platform is essentially of zero value. HN feels much more like a community, and some of the forums I frequent are even more so, despite being largely undiscoverable and frosty to newcomers.