For the past four decades, NASA has had to rely on television above all else to relay the images from space that instilled in Americans a sense of wonder and possibility, emotions key to keeping the taxpayer support coming. Now video on the Web looks poised to take over a large part of that critical role.

For NASA's July Deep Impact mission, 3.1 million visitors logged 33 million page views in just 24 hours to watch a spacecraft the size of a coffee table slam against the Tempel 1 comet at 23,000 mph. For the recent space shuttle Discovery launch, NASA estimates there were about 4.3 million user sessions and 28 million page views, including 433,000 simultaneous streams of video for the live launch.

"We want to keep NASA front and center and capture the imagination of the viewer," says Brian Dunbar, NASA's Internet services manager. "And the Web is a good way to reach kids. In fact, it may be the best way."

NASA has learned what many businesses soon will: Your customers are ready to use video over the Web. Now it's up to business leaders to figure out what of value they can deliver over what will quickly become a critical communication channel.

Video over the Web isn't going to win any Academy Awards. The quality is only OK, and the programming available ranges from the compelling, such as NASA or the Live 8 concert, to the inane, like some video blogs. But America Online says 5 million people tuned in to the July 2 Live 8 concert, which it broadcast with seven separate feeds so viewers could control what they watched during the daylong concert, which also ran on MTV, VH1, and ABC. Media companies are racing to embrace video on the Web, from AOL, Google, and Yahoo testing video search tools to traditional print and broadcast organizations trying to figure out how Web viewers want their video.

"People are moving to video because they can," says Eric Schmidt, Microsoft's group product manager for digital media platforms. "Over the past several years, technology has diminished the barriers to entry." That tech includes greater network bandwidth, blazing-fast PC processors, and Microsoft and RealNetworks Inc. software that makes video available to users from any desktop. Inexpensive software and Webcams make it easier for companies to create and deliver their own multimedia messages.

But like NASA, it's how nonmedia businesses use this power of moving images to speak directly to their customers and partners that could provide some of the most interesting and valuable uses of video on the Web.

Robert Wood Johnson University Hospital in New Brunswick, N.J., has for more than two years offered doctors, medical students, and prospective patients the ability to tune in to live or archived video of doctors performing surgeries to relieve back pain for a car-accident victim, prevent a patient's heart aneurysm from rupturing, and treat a condition called hyperhidrosis, which causes excessive sweating. Each video begins with preinterviews with the surgeons performing the procedures and includes footage of the actual surgery.

Web video is sure to play a more-important role in selling products online. Victoria's Secret tried the online fashion show as far back as 1999, though it was clobbered by overwhelming demand and slow dial-up connections. Now the site features near-broadcast-quality video of new products. Same for BMW. Most automakers don't yet have video on their sites. But BMW--apparently secure in the notion that Beemer drivers wouldn't be caught dead on dial-up--puts quick clips of its BMW 3 Series Touring in motion on its site. Major League Baseball has highlight clips on its MLB.com site and lets fans get clips delivered to their mobile phones for a fee.

BuyCostumes.com is an example of smaller companies ready to take a risk on video. For just over $100,000, the E-retailer filmed a fashion show of its costumes, which it's hoping will help boost annual sales more than 40% this year to greater than $25 million. With people spending as much as $850 for a Collector's Supreme Edition Darth Vader, or even $50 for a Tom Arma Signature baby's dinosaur costume, the company thinks the opportunity is now for combining video and E-commerce. "It's hard to get a feel in a still image what a costume's made of, what it looks like on a person, how it hangs," chief operating officer Daniel Haight says.

Yet BuyCostumes also shows the challenges of managing the technology. The company decided it would be too difficult and costly to manage an unpredictable number of streams, so it's running the five-hour fashion show at BuyCostumes.TV as one stream--exactly like TV--in which people watch what's airing at the scheduled time. The company, which ships about 20,000 boxes a day in the peak season before Halloween, is hoping for more than 5 million views. As companies build a stockpile of product videos, expect to see far more offering video snippets for individual products, so shoppers can see them in motion before they buy.

That's how a few sellers of high-end real estate are using Web-based video. Kouros Tavakoli, a real-estate agent with Decker Bullock Realty Inc., offers video tours of multimillion-dollar luxury homes near San Francisco, while Bahamas-based James Sarles Realty has hired Real Estate Video Imaging Systems Inc. to create Web-based video clips that it hopes can make use of lush settings and expansive interiors to help close deals on pricey houses without the need for clients to first visit the island.

LiveVault Corp., a provider of managed backup and recovery services, tried bringing video to the direct-marketing realm in its competition with larger rivals such as EMC Corp. and Hitachi. Its gambit was to spend more than $250,000 on a campaign that included a seven-minute clip of actor John Cleese (of Monty Python fame) doing his bit as Dr. Harold Twain Weck, director of the fictitious Institute for Backup Trauma. "The richer the media, the more successful we've been in educating and helping our prospects understand what we do best," CEO Bob Cramer says.