Can you do the same thing in IE or Mozilla? I bet a lot of people would like to be able to type lj:username to go to http://www.livejournal.com/users/username, or ljf: to go to their friends page (filtered by group if an argument is given), or whatever.
Along the same lines, it'd be cool if someone could write an IE5 custom tool band for LiveJournal, along the same lines as the Google toolbar.