Instead, it's typically a more prosaic end: humanity wiped out because an AI tasked with a simple goal (say, creating paper clips, an example that is often used) requisitions all the energy and raw materials on Earth to relentlessly churn out paper clips, outsmarting and out-maneuvering all human attempts to stop it.
He'd provide an Internet marketplace where small and medium-size businesses could buy routine supplies, from paper clips to fluorescent lighting fixtures.