If you google and sleuth a bit, you’ll see this issue has been going on since last summer and has gotten progressively worse.
While I can understand the logic behind “happening on multiple ISPs therefore it must be Netflix”, I don’t agree.
Netflix now accounts for about 1/3 of all internet traffic and has about 75% of the video streaming segment. Netflix’s growth/domination is hurting ISPs in 2 ways. The ISPs don’t want to be just a pipe, they want you paying for their streaming service (FIOS has Redbook, Comcast, Xfinity TV etc etc) and they are getting killed by Netflix. To add insult to injury their networks are getting killed with all the Netflix growth. It would kind of stink if you owned a business to have to spend money to support a competitor. There is an unbelievable amount of money at stake here.
Bottom line is that I believe the ISPs are doing the absolute minimum in terms of paying for / maintaining their peering / CDN agreements. That is why just some people are seeing this and really does depend where you are. They are perfectly happy to run their ports at full capacity which is when people will see lower bitrates and buffering. Netflix offered up Open Connect last year as their solution to this issue, but so far none of the big US ISPs have implemented it. Again why help a competitor?
http://gigaom.com/2013/06/17/having-problems-with-your-netflix-you-can-blame-verizon/
http://gigaom.com/2013/06/17/time-warner-cable-no-we-dont-throttle-youtube-its-all-about-peering/
