I like the sharing video features. I don't know how many times I'll have friends ask me how to do certain parts of games. Now, instead of trying to tell them and explain it and failing and repeating over and over, I can simply show them. Sure, it's nice for them to figure it out on their own, but I occasionally have more free time than they do, so it's much easier for them this way. And then sometimes after knowing how to do it, they'll find an easier part.
It's also useful for things like easter eggs, now when found, you can easily share it with friends or the world. Like the video on Youtube doing a complete breakdown analysis of the Metal Gear Solid V trailer, where you can see tons of interesting, odd and confusing stuff if you pay attention everywhere.
