As surely as it crashed over the publishing and music industries, the Internet is inexorably remaking the world of education.
Stanford University President John Hennessy has likened the latest wave of online education -- from simple video lectures to entire degrees earned online -- to a tsunami.
"What I told my colleagues is there's a tsunami coming," he said recently. "I can't tell you exactly how it's going to break, but my goal is to try to surf it, not to just stand there."
Though Stanford and others have dabbled in distance learning for decades, recent advances have dramatically improved the student experience, making it more interactive and unleashing a torrent of renewed interest in online courses.
The global press took note when more than 100,000 people around the world signed up last fall in each of three free, online Stanford courses in computer science and artificial intelligence.
Those Stanford classes were the most powerful demonstrations yet of the latest buzzword in higher education: "MOOC" -- massive, open, online courses.
Despite the many unknowns, major universities began flocking to join MOOC startups like Palo Alto-based Coursera and Cambridge, Mass.-launched edX, which allow them to offer courses to tens or hundreds of thousands of students. Another Palo Alto startup, Udacity, aims to enroll mass numbers in courses such as Introduction to Computer Science, Introduction to Physics, Introduction to Statistics and Algorithms.
Stanford, not surprisingly, is in the thick of it, with two of the major, for-profit players -- Coursera and Udacity -- founded by Stanford professors.
And within Stanford itself, more than 40 faculty members recently applied -- and half received funding -- for grants to advance efforts in online teaching.
"The level of interest from the faculty has been building steadily," said Computer Science Professor John Mitchell, recently tapped by Hennessy to become vice-provost for online learning.
"There is nothing top-down about this. ... There is something of a start-up mood all across campus. And many faculty members really want to get the message out to potential students around the world."
Stanford's schools of business, engineering and medicine all have recently appointed associate deans to expand e-learning.
"MOOCs are not necessarily the best or only model for Stanford," Mitchell told the faculty in June. "There are many possible models, so we all need to become tech-literate and figure out what's best for us."
Another major player in global online education is also local -- the Mountain View-based nonprofit Khan Academy, which offers education at the K-12 as well as the university level.
Khan already has reached more than 6 million individual students around the world and has ridden a wave of acclaim -- including strong backing from Bill Gates and Google -- in the past two years.
MIT and Harvard also have weighed in to cosponsor another startup, the nonprofit edX, which the University of California at Berkeley and the University of Texas recently joined.
The allure of online higher education comes down in no small part to economics -- the dream of delivering quality education at a much lower price per head.
That lower cost comes in the form of reaching large numbers of people, said Daniel Schwartz, a professor at Stanford's School of Education.
Coursera reports that it has more than 1 million enrolled students, while around 100,000 people logged into their Udacity accounts each week this summer, according to Udacity co-founder David Stavens.
"I think one of the great appeals is that (online education) can bring a lot to scale," Schwartz said.
Stavens points to the rising cost of education and levels of student debt in creating the need for a lower-cost alternative.
From 2002 to 2012, in-state tuition for the University of California rose from $3,800 to $12,200, while non-resident tuition increased from $14,900 to $36,000. California State University tuition rose from $2,070 to $6,518 over the same period of time.
And according to the federal government's Consumer Financial Protection Bureau, outstanding student-loan debt surpassed $1 trillion in 2011.
"I think (online education) makes sense given where technology is, and I think it has to happen due to where (student) debt is in the United States today," Stavens said.
Besides lowering costs, online education could also change the quality and nature of higher education itself. A student who's now little more than a passive number in a 300-plus lecture course in a state university could -- in theory, at least -- get a much more personalized experience taking the same class online, given the rise of interactive tools.
"Flipping the classroom" -- having students absorb information online at home and then using classroom time, if there is any, for more creative and engaging pursuits that build on the material -- also could fundamentally alter the experience of higher education.
Online learning also holds the appeal of democratizing education by providing poor people in any village the opportunity to "rub minds" with the most brilliant professors on the planet.
"There's unique talent in places like Mongolia and Ghana," said Daphne Koller, a professor of engineering at Stanford and cofounder of Coursera.
Noting that students in some of those places are getting top scores in online classes, she added: "This is helping us identify some of the world's best talent to come here (to Stanford)."
In spite of the promises of online education, many urge caution about premature adoption. Former Princeton University President William Bowen -- once a skeptic who gradually has become a convert to the quality of online educational outcomes -- delivered two lectures at a recent series at Stanford aimed at taking a critical look at the newest move toward online courses.
He stressed that more evidence is needed on academic outcomes and cost effectiveness despite thousands of studies of online learning -- most of which he said had flaws.
However, Bowen recently completed a small study at Carnegie Mellon University that persuaded him online classes can produce learning outcomes equivalent to those in traditional classrooms.
Overall, universities shouldn't be defensive and should be open to experimentation with the new, he said, though there's a danger people will rush to embrace online learning before it's fully tested.
Andrew Delbanco, director of American Studies at Columbia University and author, most recently, of "College: What It Was, Is, and Should Be," likewise urged caution.
He spoke in response to Bowen and said that the key questions to ask about the rush to online courses are "What will be destroyed, and what will be innovated?"
Tsunamis, he noted, are not known for their selectivity.
A large percentage of America's college students attend overcrowded, underfunded community colleges or state institutions, he said.
If the online tsunami can wash away obstacles to educational attainment -- and barriers to learning once students get to college -- it could be a great plus, he acknowledged.
But other possible consequences to learning are more ominous, Delbanco said.
Massive online courses could accelerate a rush to a star system, in which the top professors attract a global following of hundreds of thousands of students.
For other faculty members -- those teaching languages in particular -- "the prospect is for near or total obsolescence.
"Your French teacher may be a version of Siri on your smartphone," he said.
Delbanco also worries that the pressure for revenue in the plethora of online education startups could result in shortcuts that reduce quality, making it "hard to retain the high-mindedness" that characterizes the elite pioneers of online education at places like Stanford.
"So far, universities have done little to define conflicts of interest in this brave new world that's already upon us," he said.
Delbanco also is skeptical about the quality of humanities education that a student can experience while sitting alone with a laptop -- the same venue in which he simultaneously could be shopping, chatting with friends and even surfing for porn.
He worries about the future of teacher-student interaction -- the kind that happens when a professor gets to know a student face to face in a class over time.
"Maybe it will be possible to preserve that experience ... but I'm not convinced," he said.
"I'm not convinced there's anything sequential about humanistic knowledge or learning."
In an 1838 address to graduates of the Harvard Divinity School, Ralph Waldo Emerson said, "Truly speaking, it is not instruction, but provocation, that I can receive from another soul."
"I don't think we can emphasize too much this distinction between instruction and provocation, facts versus knowledge, discipline versus inspiration, information versus insight," Delbanco said.
"A true education values and entails both."