Mozilla Labs has launched a  competition that aims to find an alternative to tabbed browsing.

After popularising the idea of tabbed browsing it now seems that the Open Source browser maker thinks the idea is old hat. Mozilla claims on its Design Challenge website that tabs worked well on slow machines on a thin internet, where ten browser sessions were 'many browser sessions.

However with more than 20 parallel sessions are quite common; the browser is more of an operating system than a data display application; we use it to manage the web as a shared hard drive, the site said.

"However, if you have more than seven or eight tabs open they become pretty much useless. And tabs don't work well if you use them with heterogeneous information. They're a good solution to keep the screen tidy for the moment," it claims.

The challenge has the catchy title, "Reinventing Tabs in the Browser - How can we create, navigate and manage multiple websites within the same browser instance?"

Part of the reason for the change might be the move to mobile computers. Mobile browsers, such as Mozilla's own Fennec, have problems switching between different tabs.