If he is at a team of 20-30 people, that's an easy figure to defend. But when stripe has over 800 engineers (maybe 400 at the time he made that tweet), that seems some kind of major exaggeration.
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]."