HotGun is a client-side search engine that doesn't use any centralized index. You're trying a demo of HotGun, which is contacting a small subnetwork composed by few peers sharing some demo contents. You can have a look to what's inside this network hitting the Search button without any query. Then, try setting a query and searching again.
Welcome to HotGun Dirty, a simple frontend to the HotGun network.