This week, the Bush campaign might have hit a key Net Election milestone without realizing it. Instead of putting up a Web site to promote a candidate, Bush actually went out on the campaign trail to promote a specific page on his Web site. And within hours, the Democratic National Committee posted a separate Web site designed to refute Bush's.

Campaigning on Internet time has finally arrived.

Capitalizing on the bottomless frustration with taxes that Americans feel in mid-April, Bush appeared at campaign stops in Arkansas and Michigan with a computer featuring his Web site's "tax calculator." The calculator (which is available in English and Spanish) purports to show how Bush's proposed tax plan "helps working Americans." Users enter their annual income, filing status, and percentage of income from a second earner, and then a database calculator spits out a tax-cut number. A married couple that makes $80,000 a year (25 percent from a "second earner") and that has two children would, the calculator claims, save $2,662 under Bush's plan.

The notion of an online tax calculator is not new. House Majority Leader Dick Armey has offered a flat-tax calculator since at least 1998, and it was also a staple of Steve Forbes' now-defunct Web site.

What is new, however, is that the Web-based tax calculator has grabbed center stage in a presidential debate. In some of this campaign's first intensive use of mass-used Internet advertising, the Bush camp last week bought banner ads on Yahoo! that read, "How much will the Bush tax cut save you?" And the campaign also sent out a widespread e-mail, promoting both the calculator and a series of charts displaying the supposed virtues of Bush's tax plan.

Indeed, given the lull in presidential coverage in the traditional media, the current "debate" over tax policy is taking place almost exclusively online. The online tax calculator is not just a reference to a debate between candidates—for the moment, it is the debate.

Consider the Democrats' response. On Monday afternoon, they launched a site called MillionairesforBush.com, featuring a chubby, cigar-puffing feline in a three-piece suit. "Let's say you're a millionaire who has raised megabucks for George W. Bush's presidential campaign," the satirical site says. "Like everyone else, you want to know, 'What's in it for me?' "

But, the site points out, the calculator on Bush's site only goes up to $100,000 a year. How is a family on the very top rungs of the income ladder to know how much they would save?

Not to worry: The Millionaires for Bush site begins with salaries of $1 million and then goes up. A married couple making $2 million in household income would, according to the Democrats, keep an extra $109,550 under Bush's tax plan. (The DNC said it was unable to provide a specific traffic figure for the parody site; however, it said that about a third of visitors to the DNC main site had clicked on it.)

The online tax "debate" has some peculiar qualities. The ability of voters to "create" their own tax cut online is, potentially, quite potent. And the use of e-mailed charts and online databases allows for more detailed numerical arguments than are usually possible, say, in a televised debate.