Earlier this morning, Brad Choate posted to his blog that he had recently discovered PubSub.com and made a few comments on it. Of course, since I've got a subscription to mentions of PubSub.com, I saw his post and answered a question he had asked about our coverage (we monitor ~1.1 million blogs). But, Brad's post was also mentioned on the kwc blog and since Brad apparently has a subscription to mentions of his name, he saw the kwc posting about seven minutes after it was created. Brad then immediately entered a comment into the kwc blog saying that he'd seen the posting. The author of kwc then mentioned Scalzi's Law of Internet Invocation: (i.e. If you name them, they will come.)
This is the sort of "automatic trackback" that gets us really excited about PubSub. Basically, what is happening is that PubSub is linking people together based on *What* they say, not just Who says it or Where it is said. (Of course, for us the "When" is always in the future...). Whether or not Brad Choate is a regular reader of the kwc blog ("Where") or even knows who the maintainer of kwc is ("Who"), he saw the posting because he was mentioned in it. Similarly, I saw both postings since they mentioned PubSub even though I don't regularly read either of their blogs (sorry 'bout that...).