Gartner Group analyst Todd Kort has discovered that the "Direct Push" email Microsoft built into Windows Mobile 5.0 to take on RIM and Good Technology isn't really push at all. It's fast pull, he tells Unstrung. The differences may be minor. But they're $ignificant.

So why would Microsoft say Windows Mobile does "push" when Kort says devices running the OS actually call the server and retrieve messages? It's not like Microsoft isn't technical enough to understand the difference between "pull" email and "push" email. (It's all about where the command to transfer the messages is initiated. RIM's BlackBerry, for example, uses true push: the server where the mail sits makes the connection to the user's device and transfers the files. Desktop email clients like Outlook and Eudora pull the mail from the server: They ask for whatever's new, and the server responds by sending the files.)

As Deep Throat said, "Follow the money."

The "fast pull" technology has two costs, says Kort. One is easy to understand: because your Pocket PC or smartphone is regularly calling up the server to see what's new, it uses up battery power faster. Not a big deal, maybe, but a factor.

The other reason is pure Microsoft. If Windows Mobile actually supported true push e-mail, then users might get their messages from anywhere, even from (gasp!) RIM servers. This is obviously unacceptable. The only servers on the planet that should be delivering email are Microsoft Exchange servers. Just ask Steve Ballmer. True push email is, in fact, perilously close to the greatest evil Microsoft can imagine, an open system.

It all comes down to customer lock-in. As it has with so many other technologies, Microsoft is loving push email to death and Windows Mobile is carrying the freight. The customer has fewer options and pays the opportunity costs of lower functionality and less battery life.

Do you suppose somebody in Redmond actually asked out loud, "Which is more important, to create an insanely great operating system for small mobile devices, or to sell Exchange servers?" We'll probably never know. But at least Gartner's Kort has shown us the answer.