The Best Growth Hack — Offer a Kick Ass Benefit to Users
If your product has some feature/usage outcome which proves extremely useful for your customers, it has a good chance of going viral. If users find something which totally amaze and delight them, they start spreading the word on their social media, blogs, websites and so on. This can start off a chain, resulting in growth at a low cost.
Linkedin was able to do this when it started allowing it’s users to create public profiles. Search engines crawl through public profiles and index them, thereby ensuring that they show up in organic results. So now users could search their name and have their Linkedin profile showing in the top 5 results on search engines, which was not possible before this unless you were a big shot.