All,

Earlier today, while fixing some network congestion problem with the bits servers, the varnish servers for bits.wikimedia.org went into an overload condition. While most affected users had incorrectly formatted wiki pages rendered due to missing javascript and css (the primary function of bits.wikimedia.org is to serve them), some experienced site slowness. The whole incident lasted for 10-15 minutes.

The incident was investigated and documented, and now available at - http://wikitech.wikimedia.org/view/Site_issue_January_2012

Regards, CT