Home, Next, Previous Bar in Opera, Mozilla
I discovered this one by accident today, but I think it's a pretty cool feature. This site (wonder if it's using gallery) has the following HTML in the <head> of its photo album pages.
<link rel="start" href="index.html" title="Home" /> <link rel="prev" href="index2.html" title="Back" /> <link rel="next" href="index4.html" title="Next" />
In Opera 7, an Opera-based bar magically appears at the top of the page, with the "Home", "Previous", and "Next" buttons enabled. Same thing on Mozilla, but only if you have the Site Navigation Bar enabled (View -> Show/Hide -> Site Navigation Bar). I also discovered that you can change the location/display of the Opera Navigation Bar at View -> Navigation Bar. I've verified that this does not work on the following browsers: IE/Win, Camino, Safari, Phoenix.
So what's the big deal - why are you writing about this? Because I think it gives a nice way to integrate workflow into a web application. You could probably put JavaScript in the "href" attribute's value to submit a form and guide a user to the next step in the process. Of course, you should still add appropriate buttons/links to your pages, but it's a nice UI for replicating choices for your users.