I mean, the EO explains it pretty well, but I'll try to expand on it.

Infastructure as a Service, IaaS, is the process of using high speed internet to run all of your business operations on equipment that your company does not own. This allows you to trim back your IT department and save space in your building by not requiring you to have a dedicated server room, which can cost a LOT in utilities depending on your operation. It "outsources" your hardware. A lot of foreign companies run these services, because they can get their labor far cheaper and it means they can offer a better price, enticing companies to use that service rather than take the expensive route of keeping equipment in house. Its far less secure as you're basically trusting a bunch of sub-minimum wage people in India or China or the Koreas with your entire company and all of your trade secrets.