ur1.ca, the URL shortener used by default by identi.ca and other StatusNet sites, has been having technical problems over the last few days, which has caused performance problems and errors for those users who depend on it.
The server is on Amazon Web Services, and the underlying hardware is scheduled for replacement. I/O is failing or timing out.
As a workaround, users should configure their URL shortening to use the internal shortener; see http://identi.ca/settings/url for details.