Thanks for replying, Krishna. I know people like being pedantic, but my URL wasn't actually relevant to the question. Thanks to another forum, I learned that WordPress has a default setting where it actually does broadcast to rpc.pingomatic.com, and apparently someone in Virginia is listening and checking feeds.
You can enable and disable it via Settings > Writing > Update services.
Originally I was worried I had some kind of potential malware phoning home whenever I made a post. Now that I know what it is, I've decided to just leave it.
