Those basic ones allowing communication: essentially directed and non-directed asynchronous sharing. And those you 1) opt-in for 2) pay for. There's a long li

Those basic ones allowing communication: essentially directed and non-directed asynchronous sharing. And those you 1) opt-in for 2) pay for. There's a long list I have, but that's a startup for another day. (Or for a time a month from now... when school lets out.)