The FCC is going to make this more and more of a reality for more people here in the states. Comcast doesn't like you streaming content they don't make $$$ off of.
I just got new internet that has a 600g monthy cap. I have never had a cap before though, so I have no idea if that is a lot or what. I don't stream but I spend a lot of time on youtube and putlocker while I work. I have two weeks to back out of the contract so, I hope I can figure out if this works for me or not.
I do a ton of video conferences for my work and i watch Twitch streams around 6-8 hours a day; every day. With that, I average about 350-400G a month in usage. You "should" be ok at 600G. I am just glad i got 1TB since I have also started streaming my game play.. lol