RedCardinal - 4:38 am on Oct 15, 2012 (gmt 0)
It's very hard to be sure what you're looking at (intentionally so I'm sure), but I've seen EMDs lose traffic on long tail and associated terms after the EMD update. These are sites that carry no ads or content that would normally be associated with Panda. Given the timing and dates this is unlikely to have been Penguin refresh, but can we trust the timings given to us by Google?
I also suspect they tweaked things further towards the middle of last week, perhaps dialling something back a little.