Whenever Netflix has been having buffering issues, they have been checking with other customers of the same internet service provider to verify that they also are having problems. If they are, Netflix has been displaying a message that puts the blame on that internet service provider for being too congested. Verizon sent Netflix a cease and desist letter to get them to stop doing this, though.
Verizon, along with other internet service providers, has been intentionally congesting the network by not upgrading the switches that connect to Netflix. They want Netflix to pay them to get faster service. FCC Chairman Tom Wheeler says he's going to step in on this, but since he's the former president of the National Cable Television Association, he might be biased in his decision. Netflix did cave and has paid both Verizon and Comcast to improve those interconnects, but it's apparently still not enough. Microsoft, Google, and Facebook all have agreements with the internet service providers to get better access to customers.
FCC to investigate Netflix-Verizon spat (CNN Money)…