As the college students settled into their seats on a recent weekday, the screen at the front of the cavernous lecture hall warned, "Under 18 not permitted."
The lights dimmed and a video clip began. An attractive woman wearing a man's white dress shirt praises the attributes of Agent Provocateur lingerie.
The actress unbuttoned her shirt and, clad only in black, lacy underwear and thigh-high stockings, climbed onto a velvet-covered mechanical bull.
She enthusiastically rode the machine for several seconds, slid off and slyly asked any men watching the video how much they enjoyed her performance.
"The world's most erotic lingerie, as proven by you," she said.
This steamy video isn't typical fare for a college course, but "Cyberporn and Society" isn't "Intro to Macroeconomics."
The new course at the University at Buffalo explores how pornography is defined and regulated and how today it is both a driving force behind technological innovation and a key part of the economy.
"We've not said pornography is just what you find in the triple-X section of the video rental store. It's something broader than that," Alex Halavais, an assistant professor of communication, said in one class.
To illustrate his points, Halavais relies on provocative images and video clips -- everything from the 2004 Super Bowl "wardrobe malfunction" to an HBO documentary on people who perform in adult films.
Some of the images would earn a PG-13 or R rating, but he's shown little explicit sex, to the likely disappointment of some members of the class.
"It's not just let's sit down and watch porn. We're all adults, and we want to learn about this and we want to open our eyes," said Kat McDonald, a sophomore from Hamburg majoring in psychology and legal studies. She said friends from Canisius College have sat in on the course to see what it's about.
School officials said it's the role of a university to tackle controversial topics in the classroom.
"I think that it's appropriate for a university to be looking at how (pornography) affects society," said W. David Penniman, dean of UB's School of Informatics, which includes the communication department.
The cyberporn course hasn't generated any formal complaints. But at least one person is concerned the course could provide a haven for young people who are addicted to pornography.
"It really depends on the motivation, both of the professor and the students taking the class," said Nate Miller, UB campus director of the Campus Crusade for Christ.
UB's cyberporn course is part of a trend nationally that is turning an academic eye to sex.
The University of Nevada Las Vegas alone offered courses on "Sociology of the Sex Industry," "Porn in the USA" and "Sex, Dance and Entertainment" -- the latter featuring a class trip to a Vegas strip club.
In recent years, the University of California at Berkeley, Massachusetts Institute of Technology and scores of other campuses have offered similar "porn studies" courses.
Halavais said he's not aware of a course that, like his, focuses on porn and its place within the Internet and the wider world.
"When we consume porn, when we engage in sex online, what are the effects on society?" Halavais asked in one class.
Pornography has driven significant social and technological change, Penniman noted.
For example, VHS beat out Betamax as the preferred format for videotape because VHS better enabled people to acquire full-length movies -- particularly pornographic movies -- for private viewing, he said.
The cyberporn course is a popular one at UB, enrolling about 400 students.
In a class this semester, after showing the lingerie ad, Halavais discussed how many laws regulating pornography stem from ideals of morality. Those ideals have evolved, he said.
Halavais first showed the class a photograph from the 2004 Super Bowl, when a nationwide audience watching the halftime show caught a brief glimpse of Janet Jackson's right breast.
"Nothing could be more American than football," he said. "Clearly, the baring of breasts became a national issue."
Halavais then showed a picture of a bridge in Venice, Italy, named the Ponte Della Tette, which translates basically into "the bridge of breasts."
During the Renaissance, courtesans were encouraged to stand on the bridge and, as gay men passed under the bridge in boats, show them their breasts in an effort to cure the men of their homosexuality.
And, in later centuries, some of the more fashionable women in Europe wore dresses that completely covered their necks and shoulders but exposed their breasts, Halavais said.
"The course pretty much deals with the standard of what's acceptable in society," said Edmund Tadros, a senior political science major from Ithaca.
Porn is an important topic given that it is a $4 billion industry and a foundation of the Internet, said John Loury, a senior communication major from Rochester.
"I think that every big state university that is worth its salt" should offer similar cutting-edge courses, Loury said.