MacSeth - 6:08 pm on May 16, 2010 (gmt 0)
Because we knew website speed was going to be a heavy thing we spend a couple of months to improve website speed big time... after that we gained traffic but after the 30th of april it is going downwards hard. We have absolutely no clue why other then Google pushing some buttons somewhere.
And what about Location?
My wild guess is that location is becoming more and more relevant. If you have a big website such as us which focusses on the whole world you are getting pushed down by local results. At least... that is something I suspect. I have no other idea other then the things which where already mentioned.