What is growth hacking?
The best way to understand growth hacking and what growth hackers do is to first understand what is meant by the term hacker. A hacker is someone who is more concerned with achieving an objective than following a prescribed process.
In other words, hackers care more about what needs to get done than how it should get done. As a result, hackers often come up with innovative ways to get things done.
For example, a hacker may be trying to get unauthorized access to a computer system. It doesn’t really matter how he does it (and there often isn’t one specifically prescribed method) so long as whatever he’s doing gets him access. Because hackers are more concerned with what needs to get done than how it should get done, they tend to be pretty anti-authoritarian and also not do so well at bigger companies where they are expected to do things a certain way.
A growth hacker is a hacker whose objective is to grow the number of users for a specific product. While lots of people consider user growth to be a marketing function, this assumes that there’s only one way to get users (namely, marketing). But this isn’t true. In fact, more and more over the last few years we’ve seen new products grow from zero to millions of users with little to no marketing at all.
There are lots of non-marketing decisions that affect user growth. Building viral product features is the most obvious, but there are many others (I’ll cover these in a future post). As a result, it doesn’t make sense to place growth hacking within a particular department like marketing or engineering. Instead, it ends up being a cross-functional role.
The idea is that for every decision a company makes, a growth hacker should ask: ”What will be the impact on growth?”
For example, when Facebook was still in its early stages they built a cross-functional growth team led by a growth hacker that touched many other departments, including Marketing, BizDev, Product, Finance and even HR. Among many other projects, the team was responsible for making Facebook available in every language through crowdsourcing, implementing a robust system for importing email contacts, and even building out a “Facebook Lite” which was eventually shut down
Over the last few years, truly innovative growth hackers have developed various frameworks and best-practices. Guys like Noah Kagan (AppSumo, Mint, Facebook), Mike Greenfield (Circle of Moms, LinkedIn), Dave McClure (500 Startups, PayPal) and many others have pioneered techniques focused on virality, email, search engine optimization & marketing.
source: by Mattan Griffel in Quora