[levocardia]

Roughly three categories: 1. Newsletters that cost a lot of money and (claim to) deliver a lot of value, examples being any number of finance/investing newsletters. 2. Massive newsletters with broad appeal. I imagine Scott Alexander, Nate Silver, Matt Yglesias, et al., are doing very well for themselves. 3. Anyone in an industry with extremely lucrative advertising opportunities. And any closely-followed reviewer of very expensive tech products (high sales price * affiliate cut) is probably doing well too.