Honestly, I think its weird that Youtube is doing this weird "Ad roller" thing.
So, Long story short, I use adblocker because half, if not, All the time i use Youtube, Its mostly to watch some stupid music video, or to check for some RT updates.
So, When i check some of hte longer video's with like 2 or 3 ad clips, You can start to tell when it'll stop and seem to rollback a bit.. Which is odd..