Due to a configuration error, a certain set of internal system outages caused the "System is down" page to be sent with LONG cache headers (7 days). This would mean that after you went to http://www.fastmail.fm and got a "System is down" message, you would get that everytime you went to http://www.fastmail.fm for the next 7 days, even though the system was working again just minutes later. This could be fixed by hitting CTRL-F5 to force a reload of the page, but most people would not know this. This has been fixed and won't happen again in the future.