It will be interesting to see what they say is follow-for-follow and what is not.

Such as I follow a lot of people. I don't have any expectation that any will follow back. It is very nice if they do. I follow them to find variety in reading which I do enjoy. I never comment asking for a follow and I never unfollow people.

I do not agree with follow for follow. People should only follow people that they want to read their stories. But the challenge is going to become that if Medium make the system to tight they are going to lose writers, and worse they will lose paying members who help fund the system.