How many websites are there in the world?

Due to the internet do not really belong to any single person, entity or organization; it is difficult to quantify the internet. There is no central control, and therefore no single "complete list" of all the different websites. Large Internet Service Providers (ISP's) will register domains and address space, which then gets split up between other ISP's, companies, and eventually the end user. Each of these address spaces are in turn will widely used for various purposes, some of which will include hosting websites.