I wrote a new post and noticed that all my Categories in the sidebar were missing - whcih meant I couldn't apply one.
I checked Manage > Categories and they're still listed there. However, when I go to Manage > Posts, nearly all my posts on the first page are missing their categories. I just went back in there, and of the four posts that still had categories listed a few minutes ago, now only three have categories... it's like they're disappearing before my eyes!
Anyone else having this problem?