@clacke there are some more differences with time-stamped videos though.
First of all, a #YouTubeClip also includes the profile of the person who clipped it, and tracks views of that specific clip, giving some sense of 'ownership' to the person who clipped it.
It also doesn't show the full video till you click on 'watch full video', which probably helps for embedding, as I've frequently run into timestamped URLs not being properly interpreted, and the embed starting at the start of the video rather than the timestamp. IIRC a timestamped video also doesn't loop as easily, which a clip does.

Not saying that most of these issues couldn't be resolved with just timestamp URL variables, but I don't think it's quite the same or bad as FB URLs.

Though, unless I am doing something wrong, the stop and/or end URL parameters actually no longer seem to work? Which would be a bad development imho...