I started a separate thread about this:
https://www.mobileread.com/forums/sho....php?p=2828123
but perhaps I shouldn't have?
Anyway, what I wrote there doesn't seem to be correct - it doesn't seem to be fetching any articles at all, starred or otherwise. Here's a blog post announcing the redesigned website:
http://blog.instapaper.com/post/85125160146
edit: Hopefully I've fixed this myself; see the other thread.