We have a big maintenance job to do this weekend. There’s a note in the Twitter UI now but it bears repeating here. We’re going to be taking Twitter offline this Saturday from 10am to 10pm PST for maintenance. This includes the Twitter.com web site, SMS interaction, IM interaction, and even API projects like Twitterrific. Tell your friends!
Update (12/15 3p): Our team has been working since early this morning on the maintenance. The good news is we’ve been able to hold off bringing down the site for a bit longer than expected (which is why twitter.com was still accessible during the day). We do anticipate bringing the service offline in a couple hours. We will update the blog with additional info on these plans.