The Farragut North Metro station hums at 8 a.m. on a weekday, with streams of commuters exiting the Red line and riding escalators into the sunshine of downtown Washington.

Before they hit the streets on Tuesday they passed giant banners advertising Drexel University Online.

Who knows how many took note of the offerings in construction management, nursing, library and information sciences and “MBA anywhere.”

Who knows how many read closely this assertion by the Philadelphia-based nonprofit university: “By utilizing the same accredited curricula, trusted faculty and Drexel community, online students receive the same education as their on-campus peers.”

There are at least a few educators, and maybe some students, who might quibble with such claims of equivalence. But what is not in dispute is that online programs are a driving force behind a surge of interest among adults in getting master’s degrees, subject of a Washington Post story the other day.

At Drexel, for instance, the number of master’s degrees awarded each year has doubled from 1,129 in 2004 to 2,382 in 2012.

Central Michigan University, a public institution not especially well known in the nation’s capital, is trying to up its master’s totals in the Washington region too. Its advertising also has been spotted in the subway.

There is little doubt why schools are pushing in this direction. It’s about money.

Among major players in the D.C. master’s market are Johns Hopkins, Georgetown, George Washington, George Mason and American universities, as well as the University of Maryland at College Park and the University of Maryland University College. Catholic, Howard and Marymount universities also have sizeable local master’s programs.

So do for-profit schools such as Strayer University.

Patricia McGuire, president of Trinity Washington University, said master’s programs help support programs for residential undergraduates at the Catholic school for women in Northeast Washington. Trinity awards about 200 master’s degrees a year, nearly the same as its annual bachelor’s degree total.

Trinity launched a school for professional studies in 2000, she said, targeting evening and weekend students (men and women). It offers undergraduate and graduate degrees, including master’s programs in business administration, communication and international security studies.

“You need to develop revenue streams to help support your undergraduate college,” McGuire said. “And this is one. It's a win-win.”

McGuire said nonprofit colleges and universities, at a time of increased competition for students, should be clear about how and why they pursue revenue.

“If it cross-subsidizes other programs, there’s no shame in it,” she said. But if the money is not about supporting education, that’s another matter. “If it’s for building the president’s house, it is shameful.”