The improvements brought along with Firefox 3 made me much happier to be using the browser, on top of demonstrating that Mozilla is still responding to user feedback. They are taking that another step further for their future browser endeavors, putting out an open call for more than just feedback, but what exactly individuals around the world want to see in a browser.
They have no defined intention of making these ideas into actual products - they are simply looking for "collaboration" and exploration. That is a great way to go about software development, especially in the world today where no longer is a piece of software relegated to a small portion of the population. There is no mention on how long they will be running this project, but if you ever wanted an idea heard by developers here is a great chance to not only tell them, but show them.