Comment on
I'm new to the platform and I'm quite confused
The fediverse is infinite, decentralized social media.
Unlike corporate social media (like Reddit, Twitter, Youtube, etc.), the fediverse (Lemmy, Mastodon, Pixelfed, etc.) is spread out across connected servers, run and moderated by the community members all over the world. There is no central authority, company or billionaire in charge here. It's just a bunch of users and communities talking and sharing with each other to form a big whole.
FediNSFW.app is just 1 server on the fediverse, (which happens to be running a somewhat reddit-like software called Piefed, if you care), and much like Reddit.com it is home to many users and communities.
However, unlike Reddit, FediNSFW is connected to bunch of different servers in a greater federation container even more users and communities, and users from these various servers can all interact with each other as if it was all one site. So as you browse the site you'll probably see users like "[email protected]" posting and commenting from elsewhere on the network. This is good for a lot of reasons--it's not controlled by billionaires or beholden to corporate shareholder interests, it's not easily corrupted by power-hungry admins, it's not centralized in any given country or culture, and so on.
If you're finding particular niche communities are empty or inactive, that's unfortunate, but the best thing that you can do is start posting things and being active. This is still a much smaller platform than reddit, and while there are enough users on popular communities to make it work well, it can be a problem for smaller communities for sure.