Fansub.TV uses a reverse proxy to filter/cache/pipeline requests to the webserver.
Normally the FTV error page comes up automatically indicating that there's some sort of temporary problem at the reverse-proxy level, but the issue today manifested itself in a way which caused pages (and other image, css, and js assets) to be served and cached incorrectly.
This issue normally occurs when the reverse-proxy caches bad data, but it can becomes even worse when the bad data gets cached in the browser itself. Even after the problem is fixed on the server end, the problem may still persist for various users if their browser still has a copy of the bad data. (You can actually verify this problem by testing with two different browsers, or two different computers on the same network.)
FTV also uses a third party failover service to detect and actively remove disabled servers. Unfortunately, this can also make matters worse if the failover service also has a copy of bad data AND the the user's ISPs cache the failover operation routing instead of the normal operation routing.
To fix a bunch of these problems, we've changed the user-facing infrastructure by getting rid of the failover service and by modifying the configuration of our reverse-proxies. The reverse proxies are now located in 13 different datacenters around the world where users are automatically routed to the nearest geographical location. If the connection goes down, theoretically the reverse-proxy can maintain limited service by displaying a cached version of the content. The new reverse-proxies should also be able to recognize when bad data is being served, and request new content.
New setup:
To summarize, this new setup should be better than the last.