Following Opera and Google Chrome, Firefox team has now decided to hide http:// and single trailing slashes (the slashes at the end) in the address bar (location bar). This feature is already available in Opera and Chrome, and the Firefox team believes that this will make the location bar more user-friendly.
The basic purpose of hiding the common prefix, http://, is to make URLs more visible. This will also help users to easily identify the website they are dealing with. Although, the URL prefix for encrypted pages (https://) will be displayed as usual to avoid confusion.
This feature is now live in latest nightly build of Firefox, and should land in stable channel with Firefox 7.