Facebook's changing the way News Feed videos display, but it's mobile-only for now

Facebook's experimenting with a new way to play videos uploaded to its News Feed, but not everyone will get to take part -- not yet, anyway. This new Vine-like feature, which will begin rolling out to a limited group of US-based mobile users, allows for videos viewed on mobile to play silently as a user browses the News Feed. Audio will only play when a user elects to click on the video, at which point it will expand for the duration of the clip. So far, Facebook is limiting these auto-play vide...