Quite a bit of misinformation floating around about this. The reality or the gist of it is, there is currently an ongoing 3-month trial with a small number of members. If that works out well, Medium might consider making it a feature for everyone, but as it stands, that doesn't mean you get paid for all external views, but only past a certain threshold calculated based on averages, so before people get overly excited, it's worth remembering that the payout might be as low as a few cents even after 40.000 views a month.