If you’re an avid YouTube video watcher, Mouse Over YouTube is a free Chrome extension that pops up a preview of any video you mouse over.
Install the extension, put your mouse cursor over any YouTube video thumbnail, and a preview pops up in the upper right corner of your Chrome browser window. The only request we’d direct at the developer is either the ability to adjust the mouse over delay or to simply extend the delay. As it is now the video preview starts almost instantly which can make a whole page of YouTube thumbnails like a mine field of unexpected videos.
Hit up the link below to grab a free copy.
Mouse Over YouTube [Google Chrome Extensions via Addictive Tips]