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Mozilla Firefox Addons 
Convert Youtube Videos to MP3 Format in just 2 clicks! With the MP3 Button on all Youtube Video pages!
Download Videos From YouTube is the simple way to download YouTube videos on the fly. Download YouTube videos by clicking a button underneath videos in YouTube. Save YouTube videos and songs in 1080p (HD) MP4 or FLV format.
Download YouTube videos by clicking a button underneath videos in YouTube. Save YouTube videos and songs in 1080p (HD) MP4 or FLV format.
This extension marks links to unavailable youtube videos with the strike through decoration, so that you see unavailable videos before clickling.
Automatically resumes YouTube videos from where you played them last, even videos, published on other sites.
An extension that adds direct links to download YouTube videos as MP4 and FLV. It has a simple interface and it downloads videos directly from YouTube. The extension integrates with YouTube's interface and adds a download button below the player.
Better YouTube experience. Provides 'Smart Buffer' for slow connections; auto loop; buffer preferences; quality selection; and more.
A simple, fast and free online Youtube to MP3 conversion tool which allows you to download your favorite youtube videos.
Convert your favorite YouTube videos and download them as MP3 files. So fast and easy!
Unblocks youtube videos on a page by replacing their url's with that of a proxy site
This addon lets you watch the YouTube videos with subtitles.
With this addon you can convert your YouTube, Dailymotion, Vevo and Clipfish Videos online to MP3 and MP4!
It it free, easy and very fast.
update 13.06.2014:
The addon was fixed to work with YouTube again after their recent changes.
YouTube Video Player Pop Out lets you pop out YouTube videos so that you can watch YouTube videos while you surf.
You can download as many YouTube videos as MP3 files as you want, you can even do so in a high quality format. You dont need to download any program to use that service. Everything happens in your firefox browser.
A simple and lightweight YouTube videos searching add-on! YoutubeSpot is designed for an easy way to access and search YouTube videos. It does this by finding videos based on their names or keywords and redirecting you to search page automatically.
