At the beginning of the new year our servers will be physically moving to a new location. This move will result in at least a day of downtime, likely more. We expect the downtime to begin at some time on the 1st of January but could start on the 2nd. We will work to get the site up and going again as soon as possible.
To stay up-to-date on the status you can join us in #what.cd-downtime (irc.what-network.net) during the move.