Not all those companies have their own data centers, but plenty of them would rent space in data centers. You can rent anything from individual servers owned by the data center ("dedicated servers", like what you can get from Hetzner), to space in a shared rack, to an entire 42U rack dedicated to you, to an entire cage (or several cages).
(a cage is just a part of the data center that's sectioned off in a locked metal mesh cage so only one customer can access it, while still allowing plenty of airflow to and from the servers)
A lot of people don't use it the way he used it though. He used it specifically for two sided markets (eg a service that has both businesses/advertisers and personal users) where the focus shifts to the business customers, but people have started using it to mean anything that used to be good but isn't good any more.