If you like to customize your applications' appearance, then Firefox themes probably haven't impressed you. Although there are hundreds of themes available, typically all they allow users to do is change the icons and background color of your browser -- not too exciting. Personas for Firefox offers a new way to customize the browser.
Though the project was quietly introduced last year, it recently moved into Mozilla Labs, where work has begun in earnest to give users more than just a way to change icons from blue to green. While right now Personas aren't much more than fancy skins, they're easy to change on the fly, and the prototype shows that Mozilla plans to give Firefox users more customization options than ever.