In my mind, Ken's problems with the PC can be summed up in two words: productivity and security. Ken believed that PCs made people less productive -- not more -- because they could host a multitude of distractions, like games. And because they needed constant attention from someone who knew more about the box than the user. More importantly, though, they were inherently less secure than a dumb VT100 terminal. Every PC had a disk drive that could contain sensitive data, and that disk drive could walk out the door any minute.

The iPhone reminds me of Ken. More power to us -- right there in the palm of the hand. Another triumph of the man-machine interface. More cool stuff to wow us. More brilliant packaging from Mr. Jobs, the guy who is as responsible for creating the wow of the original PC as anyone. And potentially more risk.

Does the iPhone make us more productive? Or is it a sophisticated toy? Beware, Ken might say, if you try to make it both.

How secure is the iPhone? What kinds of data does it store? Any data of a personal nature? How secure is that data? It's way more portable than the PC and way more fun. But what could happen to you as an owner of the iPhone if it winds up, even momentarily, in the palm of the wrong person?

I'm not saying that Jobs & Co. don't have answers to these questions. The question I have is this: Do you as an iPhone user know the answer to these questions? Ken would want you to know.