Some universities also offer free news servers for their students.
The free servers usually don't offer bin/audio/video groups, at least I don't know any.
If I remember correctly @ernest once described kbin as a "gateway for the fediverse" (but at the moment I don't have a source for that).
This would allow kbin to gather and integrate even more services from the fediverse - maybe
When you create a new post it is first saved on your instance (where your user is registered). Then your post will be pushed to all other instances (servers) where any user has registered the magazine (sub) you are posting to. The instances will then save the post to their database.
If you want a post to be deleted you have to contact the administrator of the original instance (as you said). once the post is deleted there, a delete message should be pushed to all other instances that received the post. The instances will then also delete the post to their database.
