When Google launched Gmail in 2004, the company wasn’t quite the all conquering data-gathering behemoth we know today. Indeed, no one could say for sure whether Google’s offering would compete successfully with those of Hotmail and Yahoo..
But Google cleverly turned a problem into a marketing ploy. With limited server space available, Google made a virtue out of scarcity. When it was launched on April Fool’s Day, it was by invitation only, starting with around 1,000 opinion formers who were able to refer friends. There are a lot of examples for that. You could also see Justin Jackson using a “Waiting List” to get access to Product People Club