An outage affected the Mozilla.com website on the day the organisation launched its Guinness World Record attempt for downloads of the new Firefox 3 browser.

The mozilla.com site was unreachable from around the world, occasionally responding with the message, "Http/1.1 Service Unavailable".

Melissa Shapiro posted a statement on the Mozilla blog to say that their servers were feeling the burn and should be back to normal shortly. An earlier post stated that the record attempt would begin today at 5pm UTC, but Shapiro announced after this time that the 24 hour period in which the downloads will be counted will begin once the site goes live.

Netcraft was able to access the Firefox 3 download page again shortly after 7pm UTC, but the Service Unavailable message was still seen occasionally. For some period before this, the page was still offering version 2 downloads, yet a Mozilla press release confirmed that Firefox 3 had indeed already been released.

A follow-up post on the Mozilla blog officially announced that the 24 hour period had begun, with Guinness counting all complete downloads of Firefox 3 before 18:16 UTC tomorrow.

The outages also affected the www.spreadfirefox.com website. Realtime performance graphs of the Mozilla website are available here.