FEELING FOOLISH, BUCKY, BECAUSE you don't know the difference between stocks and bonds or Nanook and NASDAQ? Take heart: brothers David and Tom Gardner, founders of the Motley Fool site on the Internet, long to help with these and other bottom-line questions. Launched on America Online in August 1994, Fool provides financial wisdom as well as investment tips for both pros and beginners. "In a way," says David, 29, "it's the business school of the 21st century."

Enrollment couldn't be better. With more than 6,000 online visits a day, Motley Fool, run by the Gardners and a full staff of 26, has become hot on the Net, and, thanks to an influx of ads, is expected to generate more than $3 million in revenues in 1996. The Gardners have even written a book, The Motley Fool Investment Guide, which recently cracked Business Week's bestseller list. Not bad for two guys who chose their site's name (taken from a line in Shakespeare's As You Like It) thinking "that if we totally screwed up," says David, "we could fall back on the fact that we're just fools."

Motley Fool began in 1993 as an investment newsletter published by David, who had worked briefly as a writer for Louis Rukeyser. The enterprise floundered until Tom, 27, then a grad student at the University of Montana, plugged the letter on AOL. So many calls came in that the brothers, sons of a Washington lawyer and a painter, realized that their brainchild belonged in cyberspace. Tom and David were soon working every waking hour in a shed turned office. Hiring a staff and moving to bigger quarters in Alexandria, Va., helped, but they each still put in 90-hour weeks, and they know that hard work can only take the business so far. After all, says Tom, "we still can't compete with cybersex."