YouTube has finally added thumbnail previews on desktop. Users can now mouseover any video thumbnail on the website and get a 3 second preview of the video contents. This works on certain browsers only for now (Chrome and Opera) and is not available yet on mobile. The lack of thumbnail previews made it difficult to gauge the content of the video without clicking it, even though this technology has been available on some video sites for years now. This has been taken advantage of by content creators by using "clickbait" images for the thumbnails to entice viewers into clicking on...
Source: http://www.gsmarena.com/youtube_finally_ads_thumbnail_previews_for_videos-news-26203.php
