In an interview with Doubleclick's chief executive, in today's Wall Street Journal, there's some interesting data. David Rosenblatt, in the process of selling the online advertising broker to Google, says there are only about a hundred big advertisers experimenting with online video commercials. That compares with up to 5,000 buyers of graphical ads on the web, and a full million buying text ads on Google and other search engines. To be sure, those marketers experimenting with online video spend way more than average; but it's a measure of the nascency of the new market.