He's suggesting that his writing (HN, etc) is likely to have encouraged a certain number of people to join Stripe. That's the only context; he's not suggesting anything about effort beyond that, just talking about the value of writing.

He might be going by interacting with team members and a couple dozen saying things like "I got interested in Stripe because of you talking about it" or "I was reading your blog for years, and tipped me towards joining Stripe instead of [other offer]."