I got a bump two days ago on a website that was hit by the whole Mayday thing (though my traffic actually disappeared mid April).
Traffic used to be about 75-100 per day, it dropped to about 5 per day mainly from yahoo. I checked through the whole thing with a fine tooth comb, made adjustments to keyword density, built some backlinks, and nada. Nothing seemed to work. Since about July, I had pretty much given up on it, and have just been making a small content update once a month to keep it going while I got on with other things.
Anyway, it's back, for all it's keywords, like someone flicked a switch. No idea why (no idea why it dropped in the first place because it was a strictly white hat content rich site that dates back to 2007).
I think Google is doing it's periodic updates at the moment, and perhaps some of the errors of the last update have been corrected in this update.
Anyone else have a similar experience?