Virality isn’t an indispensable feature of all successful applications, but for those where it can be hugely beneficial there are four core principles that help the virality of an application, says Daniel Tanner:
- Invitation should be a core process, that is essential to using the application – this will maximise the chances that your users do invite new users.
- Keep pulling people back in, rather than letting them forget you after the initial invitation, and make this “reminder” process also be central to the use of the application.
- Be useful even to the lone user, because that lone user is the source of all your other users.
- Remove artificial invitation limits, to recognise the reality that most invitations come from a few very active users, and help those users spread the word.
Tenner also notes–in passing–the concept of the viral loop. Andrew Chen’s take on the loop is the best I’ve read on the topic.