> * the one by Thomas Watson about the worldwide computer market needing only 5 computers The interesting thing is, the context of that quote is building-sized

> * the one by Thomas Watson about the worldwide computer market needing only 5 computers The interesting thing is, the context of that quote is building-sized computers being accessed by terminals over the phone network. Fast forward to 2017 and we have terminals (smartphones) accessing building-sized computers (datacentres) over the (wireless) phone network. We can be more charitable by treating all of a company's datacentres as one big, distributed computer. In which case, what's the world market? It's easy to pick 5 that cover a big chunk of it; e.g. Facebook, Google, Apple, Microsoft and Amazon :)