Vacuumed into huge databases around the country is information about how many times you went out to eat last month, about whether your dog prefers Alpo to Purina, about the kinds of videotapes you rent.

Details like these are sorted, digested and compiled so that computers can plop you into neatly defined categories to help determine the likelihood that you'll pay your Visa bill on time or buy a new brand of detergent or cigarettes within the next few months.

Until recently, such profiles have been available only to a few big retailers, banks and other credit services willing to pay handsomely for the right to take advantage of them.

But that could change dramatically this spring if Lotus Development Corp. follows through on plans to bring out a controversial product that has the potential to put lifestyle, demographic and income estimates of about 80 million American households into the hands of almost anyone who wants it.

A joint effort with the credit agency Equifax Inc., the product is a compact disc that would hold the names, addresses, approximate income levels and personal buying habits of people nationwide. It would mark the first time that the mammoth databases of credit bureaus and marketing powerhouses would be married with the personal computer -- a combination that is fueling questions about individuals' rights to privacy because it vastly expands how and by whom such data can be used.

Lotus says it has been barraged by some 30,000 callers and letter-writers who believe the product is a clear invasion of their privacy and don't want their names included in its data bases. The outcry has fueled industry speculation that the Cambridge, Mass., software company could be forced to pull or delay the product.

What has privacy advocates concerned is that the Lotus product appears to be moving the nation a bit closer to a day when all the information available on one person could be gathered in one place and then easily retrieved, sold or manipulated by virtually anyone.

Today, there is no simple way to retrieve all the information stored about a single individual simply by punching that person's name into a computer. While data about a specific person's creditworthiness, criminal record or driving history can be easily obtained electronically, information about an individual's lifestyle and other personal buying habits usually is retrieved only as part of a group of people with like characteristics.

The new compact disc product, to be sold by Lotus, opens the "window of vulnerability," said Evan Hendricks, the Washington publisher of Privacy Times, a newsletter on privacy issues. "Once they have established this precedent, there is nothing to stop the next guy from selling anything he wants {for use on personal computers}, from your Christmas purchases to your genetic history."

With the Lotus disc, a small business essentially would build a profile of the type of customers most likely to respond to its sales pitch. A new restaurant, for example, would specify a certain income range, age group and other criteria of people it believes would be most apt to frequent its establishment. The computer would digest all these desired traits and then spew out a tailor-made list of residents in a certain neighborhood, including their addresses.

Information for the disc was gleaned from 40 different sources, including the U.S. Census, Internal Revenue Service, Postal Service and surveys taken at 8,500 shopping centers and retailers nationwide. As one of the country's largest credit bureaus, Equifax has also drawn on its own records, which contain specific information about a person's marital status, sex, age range and likely income level.

In essence, the company creates "a profile of an individual based on their credit files," said Robert Hilles, an Equifax vice president. The most sensitive information -- estimated income and lifestyle -- is blended with that of nearby households to build a general profile for each neighborhood. And users would not be able to seek out a specific person. In other words, a user could not look up John Q. Smith on Aurora Drive, but Smith's name and address would pop up as part of a larger group of people fitting a certain profile.

The companies say this and other measures will help protect privacy. Lotus vows to sell "Marketplace: Households," as the product is known, only to businesses and nonprofit groups, although it admits policing that process will be a difficult task.

Still, privacy advocates worry that the product is a dangerous step toward the mass-marketing of personal data.

"As we go into 1991, there is no such thing in the marketer's mind as too much information," said Elgie Holstein, executive director of Bankcard Holders of America, a consumer advocacy group in Herndon. "The trend toward developing products which massage and gather information about people is irreversible."

Compuserve, a computer network of information to which anyone with a personal computer can subscribe, also has found itself vulnerable to the attack of privacy advocates with its new Phone File service.

Users of this service, which contains the names, addresses and phone numbers of millions of Americans nationwide, can type in a telephone number and learn to whom it belongs. Or, they can search for a person's exact address and phone number by designating only a name and city, or name with a state.

Computers also accelerate the gathering of data by enabling companies to more easily obtain, sort and trade information on specific people. Americans unwittingly feed the cycle simply by going about the innocuous business of everyday life. Today, dialing an 800 number can put your name and address on a list. So can cashing in a coupon -- some that arrive at your home are encoded with digits that will identify you when you trade them in. Filling out warranty cards, subscribing to magazines and booking a hotel room will likely get you into a database that will be used to pitch you more products or deluge you with solicitations.

Certain supermarkets now electronically monitor the purchases of customers who agree to participate in return for discounts.

As goods pass over the counter, scanners record the universal product code of each item, providing retailers and manufacturers feedback about their customers. Because the computer can determine which people are repeat buyers of diapers, granola or certain brands of dog food, for example, manufacturers and stores can target coupons for such items directly to those customers, thereby skirting costly mailings to uninterested consumers.

A unit of Citicorp collects purchasing data on 2 million participating shoppers at supermarket chains around the country. In one test scheme, it used the data to assemble individualized bundles of coupons for households. When the encoded coupons are turned in, manufacturers can determine who responded to what type of pitch. Coca-Cola, for example, could use such a technique to try and win over Pepsi devotees.

One Southern California supermarket chain, Vons Cos., uses the Citicorp system to lure customers into departments where they're not shopping, like the fish counter or juice bar. It also cross-tabulates its customer list against larger databases to find the names and addresses of residents who don't shop at Vons -- and then it mails them special offers.

Particularly useful for marketers are the handful of huge databases that profile nearly all adult Americans. In the computers of TRW Inc., which operates both a credit bureau and a marketing information service, for example, any one of 150 million Americans can be characterized in up to 600 different categories. Some categories describe easily obtainable data, like your age and how long you've lived at your current address. Other traits are more personal. Based on previous mail-order purchases you've made, TRW may classify you as a health and fitness fanatic, a fishing enthusiast or a literary scholar.

This kind of information comes in handy for marketers like the Sharper Image, the upscale catalogue and store-front retailer. The firm keeps one list of its own 800,000 mail-order buyers and another of 1.2 million people who have shopped at its retail stores. Every 18 months, the company learns considerably more about who these people are by supplying the names to National Demographics & Lifestyles, a Denver outfit with detailed characterizations of 30 million people gleaned from product registration forms returned by buyers. National Demographics matches Sharper Image's customers against names in its own database, then concocts a statistical description.

The most recent finding was something like this: The typical Sharper Image buyer is male, between the ages of 45 and 55, with a household income of $70,000. National Demographics then reaches into its database and supplies the retailer with the names of thousands more Americans who fit that description.

To build its roster of prospective customers even further, Sharper Image selects three dozen narrower lists every few months from the more than 10,000 specialized mailing lists for rent. Among those it has found fruitful: the list of mail-order and retail buyers of Hoffritz cutlery and the list of 427,315 mail-order buyers of motor-vehicle radar detectors.

List owners also can take their screening a step further by turning to a credit bureau like TRW, which can winnow down a list to include only people who hold a certain number of credit cards or maintain specified balances. The resulting names would go to a third-party mailer so the credit information is not revealed to the business that requested the screening.

All these methods of manipulating profiles are popular with advertisers, who say computerization helps ensure that you'll get pitches that are more carefully attuned to your tastes. At worst, they say, the new schemes will cause an added clutter of gift catalogues and shampoo samples.

"Privacy advocates have been so busy fighting for privacy that they don't always realize that the most this will result in is an extra bit of mail," said professor Alan F. Westin, a Columbia University privacy expert who advises Equifax.

Such arguments are small comfort to those who have already fallen victim to abuse or errors made by mailing-list hustlers. Michael Riley, a Washington-based Time magazine reporter, jumped at the mail solicitation he received in late 1989 for a pre-approved Citibank Visa card. A few weeks later, his wife, Arline, was about to buy a blouse when the cashier told her the card was no good.

When the Rileys checked further with Citibank, they were told that their car had been repossessed, they faced $70,000 in tax liens and that they had filed for bankruptcy. As it turned out, Citibank, which had purchased its credit information from TRW, according to Riley, had confused Michael George Riley with a Michael Gilbert Riley.

Riley's problem may be more common than it seems. According to Bankcard Holders of America's Holstein, 35 percent of the people who pay to see their own credit reports find their credit information had somehow been confused with someone else's.

It is this type of horror story that has raised concerns in Europe, where a draft directive would require companies to gain explicit consent from individuals before processing any information about them.

The European movement is likely to stir up privacy concerns on Capitol Hill. Rep. Robert Wise (D-W.Va.), plans to reintroduce legislation to create a Data Protection Board that would oversee federal privacy policies and guide the private sector. And Rep. Richard H. Lehman (D-Calif.) has championed a proposal to revise the 1971 fair credit act to give consumers more control over what's in their credit files and how the data is used. Lehman, however, is relinquishing his chairmanship of the consumer affairs subcommittee.