We'll be upgrading some networking equipment on December 22 between 2:00 and 6:00 AM EST.  You might see some delays and brief outages during that maintenance window.

UPDATE: 2010/12/22: 6:30AM: Most equipment has been upgraded without any downtime.  The job ended up getting split into two pieces, so there will be another maintenance window on 12/24 as well.

UPDATE: 2010/12/24: 7:00AM: All devices have been upgraded.  We had a couple minutes of downtime around 4:00AM.  For those of you who were awake at that time to notice, our sympathies...  :)

We are now using dnswl.org's mail server whitelist to bypass greylisting, which means that for known legitimate mail servers (all 101,686 of them at the moment), greylisting will be bypassed, which means that your e-mail will arrive a little bit sooner.