In short: never give your writing away for free. Even if you don’t make money on your site at the moment, don’t give your writing away for free. On more time, all together now: don’t give your writing away for free.
Read his entire piece. You’ll come away thinking that in no way, and under no circumstance, should you give away your writing for free. I completely agree with him.
I wonder if Medium counts as giving away your writing for free? I know they are working on a monetization platform for publishers (at least, they’ve said that they are or will) but to-date I’d say that is exactly what people are doing; publishing for free but with the hope of exposure.
So every single person that has published to Medium that has not been paid (I’m sure there are many that have been paid for their pieces there) has gone against Brooks’ recommendation. Just FYI.