Feed stopped updating

I imported a load of posts from one blog into my main blog today. About 200 of them showed up on my instance (@[email protected]) with dates from 2011, but the other 1200 didn’t. I’m not worried about this (in fact, I didn’t realise this would happen!) but now new posts aren’t showing up either.

I thought it might just take some time, but the feed hasn’t changed in hours. Have I broken it?

The page I need help with: [log in to see the link]