- Prism does not seem to be included in Firefox for 64bit Fedora.
- It did not work with 32 bit firefox included with Arch Linux.
I did get it to work easily with the 32bit firefox downloaded from Mozilla's site. But Prism plugin is not compatible with FF4 beta as yet.
After these experiences, the site-specific browsing option in Chrome seems to be better and cleaner. So, I will experiment with Facebook as a desktop application using Chrome for my mother and see how she manages.