Earlier this week, it was made public by Netflix that it does indeed throttle data for its users on AT&T and Verizon networks. This came out after John Legere stated that AT&T and Verizon throttled Netflix, which of course led to his competitors denying that fact. The thing is, AT&T and Verizon were right to deny it, as they aren't throttling Netflix, and Legere was sort of right when he said Netflix is throttled on their networks. But it's Netflix that throttles themselves and not the networks themselves. Netflix said that they limit streams to 600Kbps because if they don't, it could lead to customers going over their data cap and thus lead them to watch less on mobile. Something Netflix doesn't want. If anything they want the opposite.
This has led to Facebook coming out about whether it throttles data for video consumer on mobile networks, which they say they do not. Facebook also mentioned that they have not received any requests to lower the resolution of the video that is on their site, which would then lower the bandwidth and make for a better experience for all on that network. Facebook likely doesn't care all that much about the data you use, because they know you are still going to stay with using Facebook daily.
For Facebook, video is the next big thing in terms of growth. Facebook already has over a billion daily active users, and is looking to make video a big advertising area for their platform. Seeing as video ads do pay more than typical ads that are seen on the right of your timeline. Facebook has also said that they want to share the revenue from video ads with creators, similar to what YouTube does now. This is in an effort to court more creators over to Facebook and drive in more traffic.
While Netflix may throttle data on some networks, chances are you haven't noticed it. But it looks like they might be the only ones that do throttle video data, as of right now. The reasoning behind it is sound, even if everyone doesn't agree with it.