https://www.wired.com/story/guide-net-neutrality/

Net neutrality is the idea that internet service providers like Comcast and Verizon should treat all content flowing through their cables and cell towers equally. That means they shouldn't be able to slide some data into “fast lanes” while blocking or otherwise discriminating against other material. In other words, these companies shouldn't be able to block you from accessing a service like Skype, or slow down Netflix or Hulu, in order to encourage you to keep your cable package or buy a different video-streaming service.

The Federal Communications Commission spent years, under both the Bush and Obama administrations, trying to enforce net neutrality protections. After a series of legal defeats at the hands of broadband providers, the FCC passed a sweeping net neutrality order in 2015. But in December 2017, the now Republican-controlled FCC voted to jettison that order, freeing broadband providers to block or throttle content as they see fit unless Congress or the courts block the agency's decision.