We all know that it is possible to load more than one default homepage in Firefox by separating each page that you want loaded during start up with a "|". If I wanted to load ghacks and Google by default I would add https://www.ghacks.net/ | http://www.google.com/ in the home page field of the Firefox browser. All pages listed there are then loaded in their own tabs when the browser starts.
The number of pages that you can add does not seem limited. More pages however take longer to load and may slow down the start up.
Homepage Randomizer is a Firefox extension which randomly selects one website to be loaded on start up that you have added to the list of start up sites in the homepage field. The advantage is a faster loading time, the disadvantage of course that only one website will be opened during start up and not all of them.
This can be an efficient way for webmasters that maintain many pages to check their websites. I do open and close Firefox a lot throughout the day and it really makes a big difference. The extension adds a check box to the homepage option which enables the randomization.
Update: The Homepage Randomizer add-on has not been updated since 2008. If you try to install the add-on in a recent version of Firefox, you will receive the error message that it is not compatible with that version of the browser. The add-on is only compatible with Firefox 3 and older, which means that it cannot be installed in any version of Firefox 4 or above.
Please note that forcing compatibility won't work either. If you do so you can install the extension, but it won't offer its features in the browser. It furthermore blanks the Privacy options page in the browser so that no settings can be changed anymore when it is opened.
There is no comparable extension available at this point in time. Mozilla has however improved the browser's start up performance in recent builds so that it should not make such a huge difference anymore.
Ghacks is a technology news blog that was founded in 2005 by Martin Brinkmann. It has since then become one of the most popular tech news sites on the Internet with five authors and regular contributions from freelance writers.