I don't think you were around with the Big daddy but thousands upon thousands site tanked and yes there was an aglo change for it as well.
@bwnbwn This is my second time being a senior member and I've still got quite a way to go to catch up with my other post count.* I've been around since long before Big Daddy... I barely missed Florida and read extensively about the aftermath.
Google Updates and SERP Changes - October 2009 [webmasterworld.com] Check out the first post and the linked resource for more information and where I got a fairly accurate idea Caffeine is not directly an algo change. Neither was Big Daddy. They are both infrastructure changes. The algo may have been changed shortly after the implementation of Big Daddy, but Big Daddy itself was not an algo change. It was a change to the infrastructure.
Sorry if I'm being confusing to some by being overly specific about what each is rather than just lumping everything together as one cause and effect, like many seem to do, but I personally think it's more confusing and misleading to not spell out what each is and what each does...
Big Daddy and Caffeine (the named changes) are (were) infrastructure changes.
What they're actually doing with the changeover to Caffeine is changing from the Big Daddy infrastructure to the Caffeine infrastructure... Caffeine is a change to the file system, not the algorithm directly.
* The other username was a 'late at night' decision I didn't ever really like and wasn't really 'me' but I stuck with it for a long time, because I didn't want to lose my join date or post count... One day I'd had enough and couldn't take it any more, so I took the plunge and 'became a rookie again'. I wish I'd done it a couple (few) years earlier...