Twitter CEO Ev Williams is teasing his followers: "Tomorrow just became a very big day." Just? At Twitter, tomorrow is always a very big day.

After a lot of ruckus last week about Google or Microsoft buying Twitter (they're not — yet), Twitter investor Fred Wilson came forward to say that the company wants partnerships, not a payday. And he invents a new metric: "tweet views," or the number of times someone sees a message posted on Twitter, whether it's on the Twitter website, a cell phone, Facebook, or the countless number of Twitter apps people use to read and write tweets.

What does a tweet view profit Twitter? Nothing. In making up "tweet views," Wilson is returning to a practice of the late-1990s dotcom boom: imaginary measurements for fictitious businesses.

Why blame him? Anything which can be measured can be managed. And people's expectations for Twitter — A $500 million Facebook acquisition! No, make that $1 billion from Google! — are utterly unmanageable. Twitter has next to no revenues, and no plan for making money. Pressed on this issue, Williams and his cofounder Biz Stone say that they're watching how people use the service and will come up with something based on that. Translation: They're making it up as they go along.

It's far better for Twitter to be valued based on people's imagination of what it might become, rather than the reality of what it is — a "poor man's email system," according to Google CEO Eric Schmidt, or instant messaging 2.0. (AOL hasn't figured out how to make real money off of AIM, either.)

So what's Williams's big news tomorrow? Here's a preview: The day after tomorrow is even bigger.