For Elizabeth Fortson, a senior at Georgetown Day School in Washington, this winter has been a time to search for colleges - but not nearly as hard as they've been searching for her.

An honor student and a National Merit Scholarship semifinalist, Fortson said she has filled two shopping bags with letters from colleges asking her to apply. Included are such prestigious schools as Stanford, Brown and Massachusetts Institute of Technology.

"It's kind of flattering," she said about being approached by 200 colleges, "but after a while you begin to wonder what's going on."

The flood of letters -- many of which Fortson has thrown away -- is part of a torrent of direct-mail advertising, marketing and recriting that reflects drastic changes in colleges admissions over the last decade. Campus buildings and faculties have continued to expand while the number of high school graduates has leveled off, increasing the competition for new entrants - strong students at top-ranked schools, any student at many schools.

Even Harvard, which accepts the smallest proportion of applicants of any college in the country, sends out about 5,000 letters a year inviting students to apply. Its alumni and coaches personally approach "many hundreds," said its dean of adminissions L. Fred Jewett.

At the other end of the academic spectrum, Prince George's Community College, a two-year school which accepts any high school graduate, sent out 227,000 tabloid-size class schedules last month, bearing the message, "Quality is a credit for $17.50 at Prince George's Community College."

"It really is a shopper's paradise out there," said James McClure, the guidance director at T.C. Williams High School in Alexandria. "It's not like it used to be. There's something for everybody no matter what they did in high school. Our biggest problem now is to get the youngsters and the parents to fill out the forms, not to get a college to take them."

During the 1980s the competition for students will probably become even more severe, and by 1991, because of the sharp decline in births that occurred around 1970, the number of 18-year-olds, who make up the bulk of college freshmen, will drop by about 25 percent from the peak reached last year.

"There are so many college representatives trying to get in here now," McClure continued, "that we turn lots of them away. They offer us [in the guidance office] so many lunches and dinners. We could go out with them every day if we had the time."

A recent report by the College Board said that eight out of 10 college applications are accepted nationwide. Even though a small group of well-known universities remain selective, a much larger group, the report said, accept any high school graduate.Recruiting by all types of colleges has increased substantially, it said.

Besides sending representatives to high schools, many colleges have prepared elaborate filmstrips and television tapes about themselves that are distributed to guidance offices. Across the country there are dozens of large college fairs, including one each year at the D.C. Armory, which function like trade shows with college reps setting up displays and passing out literature.

Direct-mail advertising by colleges has grown into a major enterprise, with the College Board and three competitors selling millions of names of high school seniors. College ads have proliferated in newspapers and on radio. Over the last decade a network of paid consultants and conferences has developed on student recruiting. Last year the field even got its own quartely magazine, The Higher Education Marketing Journal.

"Higher education has had a fixation with growth," said David W. Breneman, a senior fellow at the Brookings Institution. "Now they're going after almost anything that's breathing, and there's a danger that there's a qualitative downgrading of the whole enterprise. . . . A handful of institutions remain highly selective and still seem to be delivering high quality, but many others seem to be competing themselves down to the lowest common denominator."

The college officials involved in marketing and advertising generally defend them as a means to make potential students aware of more choices and to attract a stronger and more diverse student body, such as more blacks to mostly white schools and more women to engineering colleges and the military service academies.

But the process has aroused concern, particularly among state legislators, including Maryland's who vote heavy subsidies for public colleges and see the recruiting as an effort by the colleges to avoid staff and budget cuts when the demand for their services has diminished.

In Fortson's case even though she lives in the District, she has attracted considerable attention from the University of Maryland, including letters from its president and chancellor inviting her to two receptions, a football game and a dance concert. She said she was assured that if she did apply to Maryland, the application fee would be waived and she probably would receive a $500-a-year merit scholarship regardless of financial need as well as guaranteed space in a dormitory.

Despite these inducements, she didn't apply.

High school athletes -- in recent years female as well as male -- sometimes get even more attention, particularly if their academic records are strong. For instance, Cathy Grimes, a basketball star and honor student at T.C. Williams, said she, too, has received letters from more than 200 colleges. Recruiters from several dozen colleges have phoned her at home, Grimes said, including the girl's basketball coach at Harvard who phoned five times.

"She really was trying to sell her school," Grimes said, "and when i told her i wondered if my [academic] record was good enough, she told me that Harvard wasn't as hard academically as it seems. . . . You know, i used to think that all you'd see at Harvard was geniuses going around. But they told me that's not true, and now I'm starting to believe them."

Both Fortson and Grimes said most of the colleges that contacted them said their names were obtained from the College Board, a nonprofit organization of schools and colleges which sponsors the Scholastic Aptitude Tests.

For the last decade the board has sold the names of its test-taking students -- if they give permission -- to colleges that want to do recruiting. This year the price is 12 cents a name plus a $100 entry fee from each of the approximately 900 colleges participating.

About 2 million individual names and addresses are available. Colleges can ask for them by a wide variety of specifications, including SAT scores, class rank, sex, race and family income. Names can be ordered by intended college majors or by geographical areas as small as local zip codes.

In its letter to prospective applicants one of the schools involved, Hamilton College, of Clinton, N.Y., describes this Student Search as "the world's most comprehensive computer dating service."

Last year the board sold a total of 22.5 million names and made a net profit of about $1.3 million from the venture, said its director Darrell Morris.

Nationwide the biggest user of the mailing lists has been the University of Miami, which bought 345,000 names from the College Board this year. In the Washington area the largest purchaser has been George Washington University -- 65,000 names last year. But this was down from the 97,000 purchased a year earlier, when, according to university records, the direct-mail approach produced only about 100 enrolled students.

"The problem like anything else now is overkill," said GW admissions director Joseph Ruth. "A good student is inundated to the point that he doesn't even open the letters. Frankly, it's one of the least productive things we do, but we're afraid to quit. Everybody is doing everything. That's part of the problem."

One other way for colleges to reach potential students has been through videotapes and sound filmstrips cassettes placed in high school guidance offices.

Preview Inc., a Washington-based firm begun in 1979, now has film strips on 15 colleges in 100 high schools around the country, mostly in suburbs, including those around Washington.

"This is the college catalogue for the Sesame Street generation," said Preview's president Carl Allen. "The kids now won't go through a 150 page small-type book. They're used to getting things visually, and this gives it to them about colleges."

A 10-minute filmstrip produced by American University includes pictures of the monuments and public buildings of Washington, as well as its own green campus and classrooms.

"I'm afraid that many people still think our campus is in an unattractive part of the city and that Washington is an unattractive place," said Rebecca Dixon, AU's dean of admissions and financial aid. "The filmstrip enables students to see what AU looks like."

For Prince George's Community College, which draws virtually all of its students locally, the problem is getting the word out on "what we can do for them," said Ernest R. Leach, dean of student officials and head of its marketing effort.

Besides the direct-mail tabloids, the college has set up information booths in shopping centers and has even been featured in the sales circulars that the malls mail to customers' homes.

As part of its appeal, the college provides day care for 75 cents an hour, offers classes from 7 a.m. to 11 p.m. weekdays, plus weekend courses including Sunday, and has set up its registration procedures the same way airlines book flights, with clerks taking "reservations" over the telephone.

"we have an obligation to make education available to as many people as we can," Leach said. "We try to find out what it is that the customer needs, and we will build a service that that customer needs. . . . If colleges continue to build Chryslers, they'll all go bankrupt."

But to Stephen K. Bailey, an education professor at Harvard who is president of the National Academy of Education, "standards are bound to suffer" from this marketing approach.

"When there are great pressures to get students," Bailey said, "there are great pressures to keep them once they are there. . . . There's a whole series of subtle self-interest [by faculty]: you do it in the name of remediation or of giving [students] a second chance. But the result is a loss of standards that has changed the nature of higher education from a serious pursuit with quality control and high standards to a custodial function."

Among students and parents, Bailey said, the effect of recruiting can be "preverse."

"If you receive a hundred fancy colored brochures," he remarked, "it has to make you a little bit cynical and ask the question, 'If they have to push the product so hard, there must be something wrong with it.'