With it, you can download videos directly from embedded YouTube players. All you just need to do, is to hover a cursor on it and a "Download" button appears. Thereafter, you can save the video in the desired quality.
You can also use it to download videos from Facebook.com with a click from user pages, news feeds, or even comments. Move the mouse pointer over the link - a green arrow will appear. Click the arrow and choose the preferred video quality.
For Vimeo.com and Dailymotion.com, the extension forces a "Download" button to appear on the page, where you're watching a video file.
You can download SaveFrom.net Helper extension here.