Sorry for the 'Welcome to nginx!' issues we've been seeing for a bit now. It was a server configuration issue that hit us when a webserver rebooted.
Basically when the machine rebooted, nginx (software that can act as a web server) started up and then when Apache (the software Dreamwidth code uses for a web server) tried to start, it failed because nginx had already started and registered on the ports (the way web server software gets your requests).
Again, sorry for the site issues. Everything should be back to happy-times now, so let us know if you see any issues!