Facebook's Middle Mile Infrastructure

Here's a short outline: https://connectivity.fb.com/news/fiber-optic-cable/

"We will be investing in new long-haul fiber to allow direct connectivity between our data centers in Ohio, Virginia, and North Carolina."
"We will reserve a portion for our own use and make the excess available to others. This means you’ll start to see a Facebook subsidiary, Middle Mile Infrastructure, operating as a wholesale provider (or, where necessary, as a telecommunications carrier)."