The popular ViewTube userscript can open videos in external players by selecting its VTP playback option, but there are no instructions on how to do so in OS X. I played a bit with applescript and came up with an helper application that allows to launch QuickTime from ViewTube. If you are using Safari simply put the ViewTubeHandler app somewhere on your HD. For Firefox/TenFourFox there are a few extra steps: - type about:config - create a new boolean preference network.protocol-handler.expose.viewtube and set it to false - open the “First launch” html page in the attached zip file, and click the link - when asked, point Firefox to ViewTubeHandler Viewtube should now be able to open videos in QuickTime Player. I chose QuickTime because of its ubiquity and because it's one of the few applications able to open https video links on powerpc. If you have the quite more CPU efficient MPlayer 1.3 installed (linked in another thread in this forum), and if you prefer to use that, install the app in ViewTubeHandler - Mplayer.zip instead. If you open that in Script Editor you can set the path to your Mplayer binary (I assumed a Macports installation, that should give you /opt/local/bin/mplayer ), and the options to pass to the player (the ones I chose should be adequate for 360p videos playback). Another thing about ViewTube. On the script page, which at the moment seems to be down, you can see a reference to a bookmarklet called geekmonkey. This was created a long time ago by Joshie Surber to allow use of userscripts in Camino. The original page for geekmonkey is dead, but I had it in one of my hard drives so I attached it to this post.