Growth Loop
A growth loop is a self-reinforcing cycle where the output of one round of growth becomes the input for the next, so growth compounds rather than depending on a constant top-up of spend. The classic shape: a user joins, takes an action that exposes the product to new people, some of those people join, and they do the same. Content loops, viral loops, and paid loops all share this structure.
The reason loops beat funnels for a founder is leverage. A funnel is linear: you pour traffic in the top and a fraction converts, so growth stalls the moment you stop pouring. A loop reinvests its own output, so each cycle seeds the next without proportional new effort. You design the loop once, then your job is reducing friction and shortening the cycle time. The best companies stack two or three loops that feed each other.