99% of the money comes from the newsletter sponsorships. Newsletter sponsorships generally can earn wayyyy more than website ads. Incase you're interested in more details, the newsletter has ~10,000 subscribers (~50% daily, ~50% weekly) and the site gets about 30k uniques a month.
Also if anyone is wondering why the costs are so high, the main expenses are CloudFront (huge HUGE gifs) and Mailchimp. I'm sure I could reduce the costs to $50-100ish a month, but laziness.
