Once you've reached 100 followers and can get into the partner program, is your follower count more than a vanity metric? If yes, how about the ratio between how many follow you vs. how many you follow? If you write a good number of interesting and useful articles, people will follow you without having to waste your time following hundreds that you'll never read much if any of their content anyway. I agree however that leaving thoughtful comments, whether ones agreeing with the author's points or not, but hopefully adding to the conversation (and not being too much of a jerk), is a contribution, and likely gets you more readers, more reads (=more money), and more visibility.