1996.
Hotmail was solving a problem everyone was suffering but they had only $50 for marketing — so they added one line to the bottom of every email their users sent:
PS: I love you. Get your free email at Hotmail
Simple yet powerful footer that turned every user into an unpaid salesperson without them ever knowing.
You weren't seeing a random ad, you were seeing it inside a message from someone you already trusted, which made clicking feel less like an ad and more like a friend's recommendation.
New user signs up → sends emails → recipients see the footer → they sign up → loop runs forever, for free
Results?
$50 budget. $400M exit in 18 month.
PS: If you're paying to bring someone through the door, make sure they pull others in behind them. Because the best ad you'll ever run is one your customers deliver for free. 🚀
@startupbeaker