In the mini-update toolbar export on Sept 26th this blog lost its PR, i.e the value went to N/A. Previously the PR had been 3. Why this has happened I don't know. I haven't linked to any silly sites or reduced the frequency of posting.
Today I also noticed that a few inner pages on the blog have PR. I haven't noticed this before. It's strange that the older posts have PR but the blog home page is back to PR N/A. Google Analytics isn't showing any change in the level of traffic to the blog.