Hi!
Just a quick note -- we're experiencing some fun load spikes due to heavy net usage of people searching for or talking about Michael Jackson's reported death or near-death.
tech blog doesn't seem to get much updates.
The problem is quite simple, lots of people (like, million pageviews on an article in an hour) caused a cache stampede (all pageviews between invalidation and re-rendering needed parsing), and as MJ article is quite cite-heavy (and cite problems were outlined in http://article.gmane.org/gmane.science.linguistics.wikipedia.technical/41547 ;) the reparsing was very very painful on our application cluster - all apache children eventually ended up doing lots of parsing work and consuming connection slots to pretty much everything :)
Cheers, Domas