My use of the phrase "checker-playing dog" comes from the following rather lame joke:
I was visiting a friend and I saw he was playing checkers with his dog. I said, "That's amazing! You have a really brilliant dog!" and my friend said, "Nah, he's not that smart, I beat him two out of three."
I refer a technology that seem to represent some kind of a breakthrough, but isn't necessarily that useful, as a checker-playing dog. One of the classic examples is the Newton. I bought one and hauled it around for a couple of years, and found it fun to play with, but it was more about the potential of a hand-held organizer than the reality. It was heavy, didn't fit in a pocket, the interface was poor, the screen was dimly lit, and it didn't really make my life any better, except that I enjoyed it. But we all know that the Newton was one of the precursors of the Palm, the Blackberry, and the iPhone.
Some technologies seem to hang around a long time and keep reappearing in new guises, but never get past the checker-playing dog phase, like voice recognition (as a general interface vs. a useful niche) and ebook readers.
My favorite checker-playing dog right now is the home-built Fab@home machine. My intuition is that low-cost 3D printers are a disruptive technology, but they might be checker-playing dogs for a while. All I know is, I want one.