It strikes me as odd how many of these growth hacking stories describe a web analytics tool (as in the linked article), an email subscriber system, or a CMS extensions/hosting solution. Throw a rock in any direction and you'll hit 20 of these accounts.

Watching some Microconf presentations I was struck by the same thing. The talks were dominated by people who had created Wordpress plugins, created an SEO tool, or built an email autoresponder. There's a strange circularity to it - almost like a pyramid scheme.

Maybe this reflects a coincidence of interests: people who like growth hacking enough to write about it tend to create SEO tools and email drip systems.

OTOH, maybe the lessons these stories teach are too specific to be useful for other kinds of businesses.