Equnix provides data center and colocation services to companies looking for private Infrastructure systems. Not all systems need to be run in the cloud, due to privacy concerns or cost concerns and having an option to run your own data center is an option. While it is complicated and costly up front, using a provider like Equinix allows businesses to focus on their data, applications & processes while allowing a vendor to design the data center in which to run their applications.
in other words
A custom tailor that builds private infrastructure instead of suits.