From MP3s on your cell phone to television shows on your iPod to e-mails on your BlackBerry, we live in an age in which you can get just about any kind of information beamed to you anywhere. So I find it funny that I still get more than two dozen catalogs via snail mail every month. And I use them. I also still pick up the telephone to call companies and brave voice-menu hell to ask real human beings questions about stuff I plan to buy. And I still sometimes find the best way to locate what I'm looking for is to haul my physical self downtown or to the mall. Don't you?

True, sometimes it just feels good to read a genuine paper document instead of a screen. And yes, we all appreciate human contact, or at least we ought to. But usually when I end up bypassing the virtual world to do business in the actual one, it's for one reason: The Web has let me down. More specifically, I was unable to get enough information to take care of my business online. And so I end up buying things much the same way my grandparents did. Actually, less pleasantly. Service was much faster and friendlier in their day, and they didn't start off by wasting an hour on the Web.

We tend to think of our lives as being data-rich, but the fact is, most businesses are pretty stingy with the information they make available on their websites--be it product specs, buying advice, service policies, discounts, account histories, management and employee profiles, corporate information, data on partners and competitors, or troubleshooting help. And that leads to problems. For one thing, visitors who do land on your website run the risk of being frustrated by the inability to find what they need. And that's if they find you at all. Sites with inadequate information are less likely to turn up on a Google search. "The question of what ought to be put up on the Web is something that most companies still don't get," argues Michael Rappa, director of the Institute for Advanced Analytics at North Carolina State University. "If you don't push information onto the Web, customers will go somewhere else to find it." Once they've left, of course, they may never come back.

The answer: embracing what I like to think of as a "data yard sale"--that is, throwing up your company's garage door and letting everyone look inside. A lot of what customers would love to know is right there on the company's own computers. "Corporate intranets hold valuable data that could be made available to customers but isn't," notes Susan Feldman, an analyst with the consultancy IDC. One reason is that managers have long harbored the notion that restricting information is a good thing--a way of keeping rivals in the dark, encouraging shoppers to pick up the phone and call an actual salesperson, even preventing customers from finding out something that might turn them off. According to this line of thinking, sharing information means losing control over how it's used. "Businesses are caught in a Catch-22," says Thomas Vander Wal, a principal of media consultancy InfoCloud Solutions in Bethesda, Maryland. "They want to use information to better connect to customers, but they want to do it without the risks of the information being used in a negative way." What companies tend to overlook, Vander Wal says, is that the potentially negative repercussions of withholding information tend to overwhelm whatever small misfortunes might come of posting it.

The fact that companies keep loads of potentially useful information locked in internal databases behind firewalls has had the effect of creating a second Web that isn't accessible to the world--including search engines like Google (NASDAQ:GOOG). One company that is trying to open up some of this dark Web is GlobalSpec, which operates a "vertical search engine" that aggregates data on 2.2 million industrial products based on 175 million specifications, often providing far more information about the products than the manufacturers put on their own sites. GlobalSpec makes money by charging companies anywhere from $5,000 to $500,000 to post their proprietary databases and catalogs; currently, 3.5 million engineers and purchasing agents are signed up to search.

Portals like GlobalSpec can help crack the dark Web, but that doesn't mean companies shouldn't be thinking about making their own sites more information-rich. Michael Ladd, CEO of Euchner-USA, a maker of electronic components in East Syracuse, New York, had his consciousness raised to the limitations of his own website via his experience shopping online. "I noticed that when I don't see the information I want on a company's website, 0.3 seconds later I'm at a different website," says Ladd. "That made me think about the information we offer at our own site."

Today, the Euchner-USA website isn't the prettiest in the world. But if you're looking for, say, a switch, you'll probably find the information you're looking for. The site lets users search by category and subcategory of switch or by part number, browse any section of the catalog, and download spec sheets and CAD drawings. Distributors can directly access inventory data and create a quote for a customer that can later be converted to an order with a click. If a visitor doesn't know much about switches, the site will walk him or her through product types. "The site has gotten a little crammed," acknowledges Ladd. "But it's worth it to give a customer the ability to get all the specs on a part from us rather than having a competitor tell him about it." The payoff for the company, which also lists its data on GlobalSpec, has been considerable. Ladd says that every time Euchner-USA adds new data or search capabilities to its website, sales climb almost immediately. That's what happened in January when the company added the ability to query technical specialists on the site.

Managers at Park Tool, a manufacturer of bicycle repair tools in St. Paul, also realized the company was sitting on a vast amount of invaluable information: the trove of bicycle repair and maintenance know-how employees had accumulated since the company's founding in 1963. So the company decided to post detailed instructions on 116 different repairs, complete with photos--and, of course, links to the Park tools needed for each job. Park also noticed that bike shops trying to order a replacement component for a broken tool, such as a bike stand, often ended up calling because they didn't know the right name or part number and couldn't figure it out on the website. So Park added large diagrams of its tools to the site. The instructions and diagrams "communicate our position as the authority on bicycle tools," says Bill Armas, Park's director of marketing. Traffic this year is running 38 percent ahead of the same period last year, Armas says, and he expects it to grow even more when the company adds videos to its repair instructions.

Needless to say, you can't be completely indiscriminate about what information you post online. It would be criminally negligent to open up databases of customer information, for example, and even posting too much employee information could cause problems. And yes, your competitors will probably be even more thrilled than your customers to get a look at some of the data you might end up throwing out there. Is it worth it? Absolutely, says Michael Ladd--provided you have faith in your products and services. "I'm sure that our competition uses some of this information as a means of comparison, but that's not something we're afraid of," he says. "In fact, we welcome it." Bill Armas says much the same, noting that while the diagrams of the company's products would be a great aid to anyone hoping to churn out knockoffs, he doesn't believe any competitors could do it with sufficient precision to constitute a threat.

Couldn't a minimalist approach to sharing information work for some companies? Thomas Vander Wal notes that Apple (NASDAQ:AAPL) has actually made a successful strategy out of keeping its customers ill-informed--it's all part of the brand's high-fashion mystique. But he warns others not to try this at home. "I can't think of anyone else that would work for," he says.

Contributing editor David H. Freedman (whatsnext@inc.com) is a Boston-based author of several books about business and technology.