I've been using Facebook for a few months, and I'm sorry I ever stopped using it. It's an important product to understand because so many people use it. If I want to participate in the evolution of post-Facebook technology, I have to have a good idea of what Facebook is. I made Mistake #1 that technologists make. I ain't perfect.

• I also thought the iPad was a dud, to show how wrong I can be.

Now I think I understand what Facebook is and isn't. It is a place to post pictures of family and friends, to keep people posted on what's up with you. People who you have personal relationships with. It's different from Twitter and LinkedIn, the former is for news, and the latter is for professional relationships. There probably isn't anything unique to each technology that makes it better or worse suited to one of these applications, rather it's the users who have decided how to position them.

Position. That's a very important word, and an idea that all technologists should study and understand. I first focused on it in a great book by Al Ries and Jack Trout called Positioning, the Battle for Your Mind. An even better place to start is the more refined Marketing Warfare, which explores the same ideas as Positioning, viewed as warfare, with the principles of Clausewitz, the great Polish general and writer, as the structure to hang the story off.

What Ries and Trout would tell Mark Zuckerberg, who wants Facebook to be doing what Twitter is doing, is that it can't and it won't. But there is a way to compete with Twitter -- start a new product, with a different name, and position it clearly in the users' minds as a new better Twitter. With some feature Twitter doesn't have, or better, one that Twitter can't have -- that has high value for users.

The classic example in the world of Ries and Trout are the Cola Wars. At the beginning, Coke was #1 and there really was no #2. Until Pepsi discovered that people, if given a choice, would buy as much cola as they could. If the competition sold a tasty cola beverage in a 6.5-ounce bottle, touting it as the perfect size for all, offer a 12-ounce bottle at the same price. And voila, a strong #2 is born. People really did want more. And get this -- Coke had a huge installed base of vending machines that could only serve the smaller bottles. Ooops.

So if I were advising Zuck, I'd say this. Quietly off on the side have a few of your best developers do a total clone of Twitter, but instead of a 140-character limit, make it 240 characters. Add a few nice features beyond that, like the ability to delete a message in your inbox, to get rid of turds without having to block the sender, and offer it up as your answer to Twitter. Leave Facebook right where it is, as the family-friendly networking environment. The DisneyLand of the online world. The next Arab Spring can happen on your Twitter clone.