Parvenu , it is possible that the you tube servers are extremely busy , but if you have this problem all the time it's more than likely your connection speed ain't quick enough.
Quote: Also, I can see that it seems to be loading again. Is it Buffering?
I would say so. Buffering in simple terms means a piece of the clip is downloaded to your PC , lets say for example 1 minutes worth. While you are watching this piece another minutes worth is being downloaded. Now in practice by the time you've watched the first piece , the second piece has fully downloaded and they join together to give you have a seamless picture. This process continues throughout the clip to give you a video without any breaks. However if your connection speed is not fast enough you won't have a problem watching the first piece of the clip , but the second piece will not have fully downloaded by the time you've watched the first , causing the clip to appear to stop. Once it's fully downloaded the clip will then start again. Unfortunately i don't think there's a lot you can do about it.