That’s the first thing I thought about too. OP how do you sell your side projects? Does people just reach out or are you actively looking for people interested in buying?

I think "sold" probably doesn't mean what you think it means here. Have you looked at the projects? Nearly all of them are just statics lists of things. Like "a list of all country flags" or "a list of modern inventions"

Maybe it was some SEO related sale with the domain and bit of ad revenue that someone bought for $100, which probably isn't the definition of selling a side project that most users on HN have. In fact, looking at the domains, the domains were probably worth more than the content on those sites.

That's why I originally flagged this post because I thought it was a bit misleading. I didn't think most people here would consider simple lists of things as side projects.

I think this is a good clarification, although I think it's still a solid accomplishment.

If you follow the sold side projects, a majority (maybe all; I didn't check) are now defunct/parked, which corroborates your hypothesis.

I'd love to make $100 on a side project

Agreed that the number sold is high! Although of the sold ones I clicked on 3/4 were no longer online at all, so I would guess the amounts sold for vary widely.

Still… it’s a pretty fun list!