Bearing in mind the PPC challenge that's in the works, I thought I'd address the problem of Youtube playback again but this time on my lowest spec OSX Mac, a 500Mhz G3 iMac with 512MB RAM. As Youtube have made 3gp playback with a spoofed user agent impossible, the next step up is iPad compatible mp4 - so running either Safari or Tiger Webkit with a mobile device user agent (either the built in iPad one or your own choice) you can get a Youtube browser that is quick to use and playback of a small, low quality mp4 in browser works fine, albeit running the CPU at 100% As I'm aiming for the most efficient CPU use plus video quality, below is the best solution I've found on the G3 iMac: Webkit/mobile user agent/PPC Media Center/mplayer. After browsing for your video, copy the link and open PPC MC, choose Download SD and let it do it's stuff. I've found there is only one playback option for 360P mp4 on the G3 - mplayer. Maybe G3's above 500Mhz might have luck with Quicktime, VLC etc but for mine this is the only solution. Using the shortcut script I've detailed here: http://forums.macrumors.com/threads/mplayer-script-for-struggling-macs.1836256/ mplayer plays the video fine - I've shown it windowed here but full screen is the optimal choice. All in all, it's quite remarkable the iMac can do this considering the lack of Altivec on the G3.