Weren't they were giving away a free membership for a limited time? Now, the membership is always free. I'm not sure if they "discovered" that free is the rig

Weren't they were giving away a free membership for a limited time? Now, the membership is always free. I'm not sure if they "discovered" that free is the right price for membership, or if the "giving away" part was always just a marketing gimmick / viral growth motivator. Did anybody ever actually pay for a Jet membership? edit: I might be mis-remembering what their initial marketing was, but this feels like part of a strategy to never really make any money from charging for membership.