Growth Hacking is essentially thinking of the role of a marketer as someone who is a chef instead of a waiter, which marketers have been traditionally.

Good marketing is generally baked into the product/service itself. In the traditional model, a company would make something and then think about marketing. While the marketer might have ideas to make the product better, generally all they can do is create a better presentation for what is already made.

The concept of growth hacking isn't anything new, as many companies have included marketing in the product creation. The only change is that analytics are becoming better and the cost of tweaking a product or service once it's in the market is decreasing.