A month ago, Florida Sen. Jim Horne requested a presentation to his Fiscal Resource Committee from the state Revenue Department. He recalls how, across the screen, the presenter flashed current forecasts of the growth of sales via the Internet.

One number in particular got the legislator’s attention: Florida stands to lose $1 billion a year in sales-tax revenues by 2002 because of transactions over the Internet that, under existing rules, are exempt from taxation.