Are you really going to die? Or is someone just trying to sell you something?

The best-known examples of successful “growth hacks” — low-cost alternatives to traditional marketing — have been executed by tech companies. There’s the story of how Airbnb scraped Craigslist, the Dropbox referral program that went viral, and the classic example of Hotmail adding “Get your free email at Hotmail” tagline to the end of every email. (Ah…