I am new and signed up using kbin cafe but seem to be able to post in kbin social. I am guessing each website is like its own email service from what I can see. Though I am not sure if the owner of kbin social is the same as the owner of kbin cafe. I take it anyone can set up their own kbin site and connect it to the other kbin sites?
No, kbin.cafe is not run by the same person that runs kbin.social; here’s a post by the owner of kbin.cafe and @ernest is the owner of kbin.social and the main developer of kbin. As you mentioned, kbin works similar to an email service, so different kbins (and lemmys and mastodons) can communicate with each other.
That is really cool. I dont go online often but I like that they can all communicate.