Planned site maintenance will mean the site will be temporarily unavailable for a period today (Saturday November 19th). For around an hour from 20:00 GMT / 15:00 ET / 12:00 PT, it will not be possible to log into the site. This will mean commenting, forums and challenges will be read-only during this period. A banner across the top of the page will make clear when this work is in progress and we hope to bring an improved user experience as a result of the work. We appreciate your patience.

Update 15:44 PT: We've completed the necessary maintenance, and site functionality has been restored. However, due to the inherent latency in DNS (Domain Name System) propagation, a very small percentage of users may be unable to post to our forums for the next 24-48 hours. If these issues persist, or if you continue to experience performance or functionality problems with other areas of the site, please feel free to send feedback via the link at the bottom of this page.