Google have been making changed in Youtube. but in the process making youtube worse with every "improvement" they make.
First they removed the pause video feature. And introduced a "feature" that lets buffer part of videos in "slices". Their aim was to let the video buffer dynamically according to the speed of broadband. For this to take effect they removed the ability to let user select the quality according to their choice. And now even if you want to watch a video in just 360p, Youtube automatically changes quality on the fly, many times taking it to higher quality like 720p. Needless to say, it makes buffering even worse.
Since they introduces this feature of buffering in "slices", it stops the buffering if you pause the video, and then automatically starts to buffer again, if you unpause it. This have been a major annoyance for those with low bandwidth. This also makes the video rebuffer when you rewind, since youtube "buffers dynamically in slices".
Just recently youtube also have come under flak, for making users to "activate" Google+ account, just to comment on a YT video. Well, Google is making youtube suck more and more!