Looking at my referrals, I see a visitor from TechCrunch. Looking on the TechCrunch site, I don't see any link to my blog. However, looking at the results delivered by the Sphere It widget (shown below), I can see how this happened.
So, Sphere is driving blog to blog traffic and monetizing it via placing adverts in the pop up. This is different to the Sphere It approach used on media sites which drove traffic directly to the Sphere site itself. The real challenge here - and the real need for a more in-depth review - lies in the quality of matching algorithm. These are not link based matches (though there will be some amount of that of course), but (intended to be) meaning based. The post that is mentioned above is not about the TechCrunch article, nor is it about the company being discussed in the article. The TechCrunch post talks about a new image search application, and my post is about a search for image search systems - pretty removed, though there is some sort of connection. My first guess, therefore, is that Sphere's technology is looking for significant phrases in the posts (words and phrases that differentiate this post from others) and then cross indexing them. It's probably doing this as well as a number of other things.