Just do a search in your favorite blog search engine, like this one at Technorati, for the phrase “temporary post used for style detection”. That’s the name of the post that Windows Live Writer creates (and sometimes leaves behind, forcing manual deletion). Rick Segal has a great word/term for this – it leaves a turd on your blog. 😉
Theorhetically, no one would ever see this little autogenerated style post, except when they do. You see, people who use an aggregator service that accepts pings (like Bloglines does) for updated posts will aggregate that “turd” post immediately, so it shows up when you’re reading feeds. I’ve seen dozens of them in the last 12 hours. Also, if you ping blog search engines, it will get indexed there, too, as evidenced by the 860 results for “temporary post used for style detection” in Technorati right now. I believe that WordPress is set up to ping http://rpc.pingomatic.com automatically for new posts (I know mine install of WordPress does), and Pingomatic will send out pings to other services, like Bloglines and Technorati.
So I guess the real question is, was this an unintended consquence of the “style detection” that Windows Live Writer does (a.k.a. the “turd” theory), or a clever way to track and measure how many people are using the tool?