Migod I am so confused by all the buttons and icons. As I continue to try and figure this out I welcome your patience. I'm doing a lot of searching and trying to figure out what things like hashtags and how @users work.
@real_dreamer mastodon is FEDERATED. As in, many number of people can host their own instances and they can interact. When you @ users, you have to @username@servername because the software won't know who you're tryuing to @
1.) No idea what pound sign does yet
2.) There are 4 privacy settings on the lower left hand side of the box you type into. Public, Unlisted, Followers Only, Direct.
Public: Everyone can see
Unlisted, as in not viewable from the time line
Followers: Only your followers can see it
Direct: Only you and the person you pinged can see it, pinged as in @'d them
3.) The feed is in the global or local timeline as in, global will allow you to view everything (unless the server your in blocks an instance for being abusive).
4.) Instances are other servers hosting the mastodon software with a domain name as far as i can tell.
5.) no idea about your kinks? o.O
Forgot to add in 3 that local will let you see everything in YOUR instance only. So far it looks like the pound sign doesn't do anything.