3. The key called exclusivity

Remember how you had to ask your friends who are Gmail account holders to send you an invite so that you too can have an account. Keeping your product exclusive is one of the most effective strategies; it makes users crave for the product more and more. When Facebook started off, it was available only to the Harvard students. This made the world outside Harvard highly enthusiastic about what Facebook was and why is it only available at Harvard. Undoubtedly, when Facebook was launched for the World Wide Web, it simply became a sensation.