I’ve had an unusual burst of inbound links to this site lately, and it just occurred to me last night that there are no visible trackbacks or pingbacks.
Hmmm. After temporarily changing themes, temporarily disabling plug-ins that might interfere with trackbacks and comments such as Akismet (which is absolutely wonderful, BTW!) and No Self Pings, I eventually stumbled upon the real cause:
My custom permalink structure lacked a trailing slash.
I turned on trailing slashes (i.e. back to the traditional year/month/post-name pattern), and life is good. It would have been nice if The Google had known about this, or if WP had contained a warning to that effect. Since it didn’t, I’ll share it here to save the next person some pain.
So, to be clear: Don’t do this:
Do this instead:
(These screen shots are from WP 2.6.5 under Settings > Permalinks.)