Mozilla has launched its add-on website, offering users a new set of discussion tools - but culling the number of approved extensions from more than 2,000 to a couple of hundred.

Its debut had been delayed by technical problems. A notice on the Mozilla development blog explained. "We've hit some unforeseen problems...without getting into the details, we're having some issues with the way our infrastructure is caching (or not caching) the new pages. Rather than risk a slow, (and thus, frustrating) user experience at launch, we've decided to iron out the problems with the servers before deployment."

Mozilla engineer Justin Fitzhugh said that site downtime scheduled for Thursday would be used to update the add-on section. "We ran into some unexpected code and infrastructure issues with the last release, which have been resolved," Fitzhugh said.

Some Firefox users have already begun worrying about which extensions Mozilla will drop from its public site. Mozilla's Wil Clouser said "We're not deleting any extensions, we're dividing them into a public area and a sandbox area."

Those in the public area of the site will be given a Mozilla stamp of approval - an add-on editor will have approved the extension and security checks will have been run on its code - while add-ons in the "sandbox" will be available for additional user testing and comment.