My wife plays Solitaire incessantly. She's got a PhD and a professor's schedule, but nearly every time I look over at her laptop, she's reflexively sorting cards into piles, playing Freecell or some variation. She tells me it relaxes her, which seems reasonable enough, even if my idea of relaxing involves a dark room and a soft pillow.

She's not alone. Solitaire is easily the most popular computer program of all time. More popular than email or web browsing, Solitaire is often the first program people use. I used it to teach my mom how to use a mouse. It's a great example of drag-and-drop. Its UI directly maps to familiar items, making it the quintessential example of transparent usability.

So why do people keep playing it? Why do so many spend so much of their down time playing this simple, repetitive, game? Well, as best as I can figure, there's a pleasing comfort in its familiar patterns, in its meditative single focus, in its quiet sense of mild accomplishment.

There's an important lesson here, one that may well help the semantic web really take off. Months ago, I wrote that the stumbling block of the semantic web was motivating regular people to annotate their data. Given that most people keep all their email in their inbox, how do we convince everyone to tag their stuff on a regular basis?

I think we've found the answer. Here at Immuexa, we've been struggling for months to give Tidepool the reflexive mindfulness of solitaire, hoping to make the activity of tagging a pleasing and meditative habit.

And if that don't work, our instant messaging mojo should do the trick. More tomorrow.