Screenr, which is probably the best web-based screencasting application, can now be used for recording screencast videos in Linux as well in addition to Windows and Mac machines.
Video: Screenr running on 32-bit Ubuntu Linux
With Screenr, you can create HD-quality screencasts of up to 5 minutes in length using any web browser that has the Java plug-in installed. The published screencast is available as a Flash video (for embedding in web pages) and as a Quicktime (MP4) movie so anyone catch watch your screencasts on mobile devices like the iPhone.
The only downside is that everything you record with Screenr becomes available in public by default and there’s no option to create private or password-protected screencast videos.
If you enjoyed Screenr, you may also want to check this detailed comparison of all the other online screencasting tools.