Ask YC: Anyone actually making money selling ebooks/digital goods?

So, this article seems to have gotten traction on HN: http://news.ycombinator.com/item?id=516215 It's not a new idea. Tim Ferris has been preaching that since the Four Hour Work Week was published, and affiliate marketing programs are clearing houses for people doing this sort of thing. Is anyone on HN doing this, or have you done it in the past. I'd love to hear some anecdotes from this community.