According to a post on its help forum, YouTube began to experiment with video previews on the desktop a couple of weeks ago, albeit in limited fashion. But now the company seems to be ready for a wider rollout, as some users have started seeing the feature on YouTube's latest dot-com interface. As pictured above, soon you might notice a 3-second teaser when your computer's pointer hovers over a thumbnail, though it only works for videos that are longer than 30 seconds.