Title Your Mozilla Browsers

I have an idea for an add on and it is summarized as follows:

I jut thought of an idea from personal experience to be added on to
firefox. I think that you should be able to title each different web
window you have open. I am currently writing a term paper and I have a
window for music and email, a window for google books, and a window
for possible sources. Each window has multiple tabs and it's just like
a little filing system. It would be cool if I could click a window
then click the title bar (or something else) and type a title like:
'Media' for my music/email page and such. This may be just a stupid
idea but I think someone should consider it.