Pinterest recently, in a single week, received more visits than the population of Portugal. This is a 40x increase on the same period the year before.
Pinterest is a social network that allows users to share things of interest on their virtual ‘pinboards’.
By all accounts, Pinterest’s growth hasn’t always been as explosive, with relatively modest growth after launch. It didn’t experience the same early peaks of hype that many other web startups experience.
But its clear that it can now be filed under the ‘viral’ growth model.
In his book, the lean startup, Eric Ries has identified 3 patterns of growth: viral, sticky and paid.
Viral growth happens when each user that visits your site refers, on average, more than 1 new user.
For example if 100 people refer 1.1 new users each, you’ll receive 110 new users. When those users refer users, you’ll receive 121 new users. Then 133.1 etc.
If they refer and average of below 1 new users each, the traffic from this pattern will peter out.
If your coefficient is 0.9, you’ll receive 100, 90, 81, 72.9, etc until you receive 0 new users (from user referrals).
Tools to increase viral coefficient
Pinterest uses well designed viral tools such as pin, like and repin, as well as leveraging external sharing networks such as Twitter and Facebook.
They are also using invite-only membership (or a waiting list to join). In theory, this should reduce stickiness of the site for users who discover it on their own, but will encourage those who are members to invite their friends to join them.
These features all help raise their viral coefficient to more than 1, thus experiencing the exponential growth seen in the graph above.
Interestingly, Netflix, uses a similar but more controversial method. They were recently criticized during their UK launch for making it difficult to register without connecting your facebook account to your Netflix account, effectively making it hard not to spread the service via facebook.
These well crafted tools are what Pinterest has used to lower the barrier to ensure that, on average, each user refers more than one new user. Each site can experiment with various similar ideas to try to increase their viral coefficient.
For example, we (oolone.com) launched with a ‘follow’ button on our visual search engine’s homepage. It was a button that could be clicked once to follow us on twitter. This lowered the barrier to following us on twitter, and hopefully resulted in more people being exposed to our site.
However, we are currently trialing a ‘tweet’ button on the home page. Although this raises the barriers for people to follow us on twitter, it may increase the number of tweets about our visual search engine (and therefore exposure).
These small tweaks often require constant split testing and a keen eye on relevant metrics.
However, ultimately, the key to viral growth is that the product or service needs to be good enough for people to tell other people about it. These tools are just used to augment your offering and make it easier/more desirable to spread the word.