Gmail

First Google built a superior product. Then it built excitement by making it invite-only. And by steadily increasing the number of invites allowed to its existing user base, Gmail spread from person to person until it became the most popular, and in many ways the best, free e-mail service.

When we see a product going “viral,” it’s very rarely driven by a many-to-many spread, but is instead the result of someone with a large audience broadcasting it (i.e. one-to-many).

Even though products don’t grow virally for long, it’s still absolutely worthwhile to optimize mechanisms of virality (e.g. word of mouth, invites, referrals, a remarkab

Networked products are unique because they can embed their viral growth into the product experience itself. When a product like Dropbox has a built-in feature like folder sharing, it can spread on its own. PayPal’s badges and core user-to-user payments accomplishes the same.

A few years later, the email app Mailbox launched with a similar strategy. An incredibly compelling—albeit a tad more professional—demo video racked up one hundred thousand views in less than four hours. This one-minute video, combined with a very cool interface that showed users how many other users were in front of them on the app’s waiting list,

Viral growth builds on the power of networks to acquire users, often free of charge. Product-Driven Viral Growth Viral growth is deeply misunderstood—you might read the phrase and think, is this the same thing that happens when a funny video “goes viral”? Or maybe it makes you think of an ad agency organizing a clever stunt to share on social media