It rose from 300 to 350k in EU when they introduced bnet balance gifting, no idea why did that one correlate with the spike but it happened much earlier than COD. When they announced COD they jumped from 343k to 401 back to 344 back to 381 again to 344 then 363 and it seems to be evening itself out. The jump from 300 to 350k wasn't sudden, it just creeped up, but faster than usual and didn't drop.