In a hockey stick growth projection, subscribers, sales, or profits slowly increase for a period of time. Then, at a magical moment with no related triggering event, dramatically accelerates. Somehow, the business obtains a critical mass and everything accelerates.
While hockey stick growth charts do exist (like with Pinterest), most businesses don’t have have charts that look like hockey sticks. If you’re pitching your business to investors, including a hockeystick chart in your business plan might lead them to question your credibility.