There's that memory thing, too. Explorers have a well developed sense of humor, and are often playful or just plain silly. They can do unexpectedly juvenile things, especially in uptight and serious atmospheres. You start organizing the closet, find an old picture, and start writing your family history. After a while, you impulsively start picking up the kitchen, and half way through that get on the Internet.
Attentional differences are the defining trait for ADD of course.
Most Explorers say they have no trouble paying attention to something they are very interested in, it's just that most of their day is filled is chores, tasks and assignments. And they can hyperfocus while doing something interesting. Some use herbs like Ginkgo Biloba, St. John's Wort, or drink lots of caffeine. This is true of the entrepreneur types as well as the sensation seeking types. After all, you can't bungee jump off the Internet.