If you want to skim through your Facebook news feed without stopping for each YouTube video someone posts, the Facebook Video Player extension will play videos in the upper right-hand corner of your window, allowing you to keep browsing as it plays.
I really don't need to pay that close attention to every video one of my friends posts, but it's nice to be able to play one in the background as I keep browsing on the off chance it actually is something interesting. Facebook Video Player moves that video to the other side of your browser and "floats" it over the rest of Facebook, so you can keep scrolling while the video stays in place. It's a pretty cool little extension if you're a compulsive Facebook user that doesn't want to waste more time than necessary.
Facebook Video Player is a free download and works wherever Google Chrome does.
Facebook Video Player [Chrome Web Store]