This issue arose with Utterli, but doesn't seem to be related to that service specifically. I posted an "utter" -- an audio blog post -- and when I tried to click on the permalink generated I got a 404.
The permalink was along the lines of:
the post number being used as the post slug. This is an actual post, although one I created manually, not via Utterli.
Now I can't understand why that URL doesn't work. It should be valid, I would have thought. The post does display on my home page.
My permalink settings are for a custom structure, and are:
The plugins I use are: Akismet, digg widget, Fold Page List, Kimili Flash Embed, Simple Tags, Subscribe To Comments, Theme Tester, the_excerpt Reloaded, Tweet You, Twitter Tools, WordPress Database Backup, and Yet Another Related Posts Plugin.
Any ideas why these posts don't display?