I'm afraid the idea of "chatting with only those whom you mutually follow" is very prohibitive.
Chatting and following is quite orthogonal so it won't occur to me to wait for mutual following if I just want to send to person some private notes about some comment (e.g. name of the company discussed etc).
So unless there is feature like "send request for chat" to user whom you are not following (mutually!) - the thing is still-born.
I've been a professional C, Perl, PHP and Python developer.
I'm an ex-sysadmin from the late 20th century.
These days I do more Javascript and CSS and whatnot, and promote UX and accessibility.
I'm afraid the idea of "chatting with only those whom you mutually follow" is very prohibitive.
Chatting and following is quite orthogonal so it won't occur to me to wait for mutual following if I just want to send to person some private notes about some comment (e.g. name of the company discussed etc).
So unless there is feature like "send request for chat" to user whom you are not following (mutually!) - the thing is still-born.
There are general channels, and if your profile is set up that way (Settings -> Misc -> Connect) then you can get messages from anyone.