Mozilla Labs has created a really easy way to run any web site in its own separate window. Some people may find this useful and some may ask "what’s the point?".
Well, for instance, I’m currently running Prism on a multiple monitor setup that allows me to keep Google Reader, Gmail, and our super-secret CrunchGear web-based chatting app open in three separate windows, all the while consuming far less memory than three separate extension-heavy instances of Firefox would use.
Simply download, install, and launch Prism, fill in the URL and give your app a name, and then choose if and where to create shortcuts. Easy.
Prism [Mozilla Labs Blog]