As if by magic, Automattic, the people who own WordPress, have suddenly announced an upgrade to one of their plugins that includes export to Twitter. I shall give it a try and see if my site is suddenly OK again.
I should note in passing that the more people use WordPress, the more important it becomes that plugins be reliable and regularly upgraded. I’m not surprise that Automattic want to take over many of the more popular plugin features themselves. It will probably be good for their ecosystem in the long run. But if I were a successful plugin writer I’d be a bit peeved.