I wondered how long it'd take for the BuiltWith competitors to appear after the article a few months ago (https://news.ycombinator.com/item?id=10316060).

The golden rule of business: If you're onto a sweet money-maker, don't shout about it.

I'm currently working on a competitor to a site I read about that bragged about their business model, and if they'd have kept it to themselves they'd be facing one less competitor...