I never posted about this, but for ages I've had a problem sending automatic pings to blogrolling.com when new entries are posted here. After several weeks of searching for clues off and on (apparently no form of support is available for that service anymore since it was taken over by another company, I never received any answers to the various email addresses I sent help requests to), the answer finally presented itself...
Since early July, I've been getting errors as follows:
Ping 'http://rpc.blogrolling.com/pinger' failed: HTTP error: 301 Moved Permanently
Pulling up that link manually brought up a page telling me I didn't use their service correctly, which was expected since that link wasn't meant to be used directly from a browser, but it had worked fine before that point, and there was no indication what might be wrong.
Searching the web for information on blogrolling and the 301 error found little, but finally this week I stumbled across the answer. It turns out that I needed a trailing slash at the end of the link for it to work, apparently with the automated pings, not having that was a big no-no after some change to their system, again possibly as a result of their service being taken over by another company and the back end system changed. Since putting the slash in, pings now seem to be happening, so my blog will again be appearing on the blogrolling system for those of you who use that service.