There has been a subtle change going on in the Ajaxified websites of late, with a lot of them sporting the # in their URLs, like how named anchors work on a page.

https://mail.google.com/mail/?shva=1#inbox (Gmail Inbox)

https://mail.google.com/mail/?shva=1#inbox/11e3fbb02a77e5cc7 (Gmail message tagged 'inbox')

https://mail.google.com/mail/?shva=1#sent (Gmail sent mail folder)

http://www.orkut.co.in/Main#Home.aspx (Orkut main page)

http://www.orkut.co.in/Main#Scrapbook.aspx?rl=ms (Orkut scrapbook)

http://www.facebook.com/home.php#/profile.php?id=510934229&ref=profile (Facebook profile page link from home page)

http://www.facebook.com/friends/?ref=tn#/friends/?id=510934229&flid=0&view=status&q=&nt=0&nk=0&s=0&st=0 (Facebook 'All Friends' page)

The reason for the change is very simple: One of the casualties of the takeover of Ajax on the web has been the breakage of the 'back' and 'forward' buttons in browsers.

With this very simple change, those buttons now work again.

And that is all there is to it!

Prior Art:

Really Simple History

A Better Ajax Back Button Solution

AJAX