Here's is the list of all the supported sites, ordered alphabetically:

• 1up.com
• 220.ro
• 3sat
• 4tube
• 56.com
• 8tracks
• 9gag
• AcademicEarth:Course
• AddAnime
• anitube.se
• Aparat
• AppleTrailers
• archive.org: archive.org videos
• ARD
• arte.tv
• arte.tv:+7
• arte.tv:creative
• arte.tv:ddc
• arte.tv:future
• AUEngine
• bambuser
• bambuser:channel
• Bandcamp
• Bandcamp:album
• bbc.co.uk: BBC iPlayer
• blinkx
• blip.tv:user
• BlipTV
• Bloomberg
• BR: Bayerischer Rundfunk Mediathek
• Break
• Brightcove
• canalc2.tv
• canalplus.fr
• CBS
• channel9: Channel 9
• Chilloutzone
• Cinemassacre
• clipfish
• cliphunter
• Clipsyndicate
• cmt.com
• CNN
• CNNBlogs
• CollegeHumor
• ComedyCentral
• ComedyCentralShows: The Daily Show / Colbert Report
• CondeNast: Condé Nast media group: GQ, Glamour, Vanity Fair, Vogue, W Magazine, WIRED
• Criterion
• Crunchyroll
• CSpan: C-SPAN
• culturebox.francetvinfo.fr
• d8.tv
• dailymotion
• dailymotion:playlist
• dailymotion:user
• daum.net
• defense.gouv.fr
• DepositFiles
• Discovery
• Dotsub
• Dropbox
• EbaumsWorld
• eHow
• eitb.tv
• ElPais: El País
• Escapist
• EveryonesMixtape
• exfm: ex.fm
• ExtremeTube
• facebook
• faz.net
• fernsehkritik.tv
• fernsehkritik.tv:postecke
• Firstpost.com
• firsttv: Видеоархив - Первый канал
• Flickr
• france2.fr:generation-quoi
• FranceInter
• francetv: France 2, 3, 4, 5 and Ô
• francetvinfo.fr
• Freesound
• freespeech.org
• FunnyOrDie
• Gamekings
• GameSpot
• Gametrailers
• generic: Generic downloader that works on some sites
• Hark
• Helsinki: helsinki.fi
• HotNewHipHop
• Howcast
• HuffPost: Huffington Post
• Hypem
• ign.com
• imdb: Internet Movie Database trailers
• imdb:list: Internet Movie Database lists
• Ina
• InfoQ
• Instagram
• InternetVideoArchive
• IPrima
• ivi: ivi.ru
• ivi:compilation: ivi.ru compilations
• JadoreCettePub
• JeuxVideo
• jpopsuki.tv
• Jukebox
• justin.tv
• Kankan
• keek
• KeezMovies
• KhanAcademy
• KickStarter
• kontrtube: KontrTube.ru - Труба зовёт
• la7.tv
• lifenews: LIFE | NEWS
• LiveLeak
• livestream
• livestream:original
• lynda: lynda.com videos
• lynda:course: lynda.com online courses
• m6
• macgamestore: MacGameStore trailers
• Malemotion
• MDR
• metacafe
• Metacritic
• mixcloud
• Mofosex
• mooshare: Mooshare.biz
• MPORA
• MTV
• mtviggy.com
• muzu.tv
• MySpace
• MySpass
• myvideo
• Naver
• NBA
• NBC
• NBCNews
• ndr: NDR.de - Mediathek
• NDTV
• Newgrounds
• nfb: National Film Board of Canada
• nhl.com
• nhl.com:videocenter: NHL videocenter category
• niconico: ニコニコ動画
• Normalboots
• novamov: NovaMov
• Nowness
• nowvideo: NowVideo
• ocw.mit.edu
• Ooyala
• ORF
• PBS
• photobucket
• plus.google: Google Plus
• pluzz.francetv.fr
• podomatic
• PornHd
• PornHub
• Pornotube
• prosiebensat1: ProSiebenSat.1 Digital
• Pyvideo
• radiofrance
• RBMARadio
• RedTube
• RingTV
• RottenTomatoes
• Roxwel
• RTLnow
• rutube: Rutube videos
• rutube:channel: Rutube channels
• rutube:movie: Rutube movies
• rutube:person: Rutube person videos
• savefrom.net
• screen.yahoo:search: Yahoo screen search
• ServingSys
• Sina
• Slashdot
• Slideshare
• smotri: Smotri.com
• smotri:broadcast: Smotri.com broadcasts
• smotri:community: Smotri.com community videos
• smotri:user: Smotri.com user videos
• Sohu
• soundcloud
• soundcloud:set
• soundcloud:user
• southpark.de
• southparkstudios.com
• Space
• Spankwire
• Spiegel
• Spike
• stanfordoc: Stanford Open ClassRoom
• Statigram
• Steam
• streamcloud.eu
• StreamCZ
• Syfy
• SztvHu
• Teamcoco
• TechTalks
• techtv.mit.edu
• TED
• TF1
• ThePlatform
• ThisAV
• tinypic: tinypic.com videos
• tou.tv
• TrailerAddict (Currently broken)
• Trilulilu
• TruTube
• Tube8
• Tudou
• Tumblr
• Tutv
• tvp.pl
• Unistra
• ustream
• ustream:channel
• Vbox7
• VeeHD
• Veoh
• vesti: Вести.Ru
• Vevo
• Vice
• Viddler
• video.google:search: Google Video search
• video.mit.edu
• VideoBam
• VideoDetective
• videofy.me
• VideoPremium
• viki
• vimeo
• vimeo:album
• vimeo:channel
• vimeo:group
• vimeo:review: Review pages on vimeo
• vimeo:user
• Vine
• vk.com
• vube: Vube.com
• wat.tv
• Weibo
• Wimp
• Wistia
• WorldStarHipHop
• XHamster
• XNXX
• XTube
• XVideos
• Yahoo: Yahoo screen
• yahoo:news: Yahoo screen
• YouJizz
• Youku
• YouPorn
• youtube: YouTube.com
• youtube:channel: YouTube.com channels
• youtube:favorites: YouTube.com favourite videos, "ytfav" keyword (requires authentication)
• youtube:history: Youtube watch history, "ythistory" keyword (requires authentication)
• youtube:playlist: YouTube.com playlists
• youtube:recommended: YouTube.com recommended videos, "ytrec" keyword (requires authentication)
• youtube:search: YouTube.com searches
• youtube:search:date: YouTube.com searches, newest videos first
• youtube:show: YouTube.com (multi-season) shows
• youtube:subscriptions: YouTube.com subscriptions feed, "ytsubs" keyword(requires authentication)
• youtube:toplist: YouTube.com top lists, "yttoplist:{channel}:{list title}" (Example: "yttoplist:music:Top Tracks")
• youtube:user: YouTube.com user videos (URL or "ytuser" keyword)
• youtube:watch_later: Youtube watch later list, "ytwatchlater" keyword (requires authentication)
• ZDF