My brother spread it to me. A year or so after getting married, my brother emailed me some Mr. Money Mustache articles and I ended up reading the whole blog. I thought he was abrasive, but in a way that made me think, so I think it was effective.

That brother retired at 40, and I'm on track to retire around 45. My other siblings are also quite frugal, so I wouldn't be surprised to see them retire early as well, though my BIL seems content in his tenured professor position.