You can now download video, mp3 etc directly from YouTube, Facebook, VK.com, Vimeo etc With saveFromNet Browser extention. SaveFromNet Helper is a browser extension, which if installed on your Windows PC, will enable you download files from YouTube, Facebook, Vimeo, VK.com and more than 40 other just in one click.

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 , the extension forces a "Download" button to appear on the page, where you're watching a video file.
Download SaveFrom Helper extention Here(link below)

I Don't Need The Add-on Can I Still Download Directly?
Yes you can still download with it all You need do is to Go to the website And input the url video you want to download Then hit the download button.

How Can I Use It On Mobile Phone To Download YouTube, Facebook Video and Any other?
You can download YouTube, Facebook Video and any other video directly on you mobile phone be it Android, Symbian, ios or any other platform you are using just follow this step by step guild in the link below.

Source: http://www.techpill.net/2015/06/download-files-from-youtube-facebook.html

Nairaland dont like too many link in a single post and the too many links where provided in the tutorial, so check the source link for full details on how to use it on mobile phones!