We're seeing a larger than normal amount of spam needing to be processed which is slowing mail delivery. We're investigating further to get things sped back up to normal delivery speeds.

[UPDATE 6:20am PDT] We've refreshed our rules which identify spam much earlier in the delivery process and mail seems to be flowing much closer to normal levels now. We still have a bit of mail in the queue which will filter down over the next hour or so.

-tom