404. That’s an error.

The requested URL /bookmarks/mark?op=add&title=Station+RTHS+%28Southern_California+Network%29&annotation=&nui=1&service=bookmarks&bkmk=http%3A%2F%2Fearthquake.usgs.gov%2Fmonitoring%2Fgps%2FSouthern_California%2Frths%2F was not found on this server. That’s all we know.