CAMBRIDGE, Mass. -- With each mouse click, Mathias Crawford moves deeper into a virtually limitless library of free movies, TV shows and DVDs.
"The programs just make it so easy to use this stuff," the Harvard University sophomore said, skimming over lists of the latest "Austin Powers" and "Star Wars" movies available through file-sharing services like KaZaA.
The files live on other computers but could be quickly summoned to his over Harvard's powerful computer network.
Such services place universities in a bind: Let them run rampant, and networks get clogged and the entertainment industry gets irate. But clamp down too much, and risk intruding on students' rights.
In October, four entertainment industry groups sent a letter to 2,300 university presidents urging a tough stand on copyright infringement. And in late November, authorities at The Naval Academy seized more than 90 computers in an investigation into illegal downloading.
But schools, while saying they will fight illegal behavior, are reluctant to monitor how individuals use their computers.
"For colleges, this really is the proverbial digital rock in a digital hard place," said Casey Green of the Campus Computing Project, which studies technology on campuses.
A growing number of schools, including Harvard, Pittsburg State University in Pittsburg, Kan., and the University of Wisconsin-Madison, are trying to strike a balance with a technique called bandwidth or packet "shaping."
By limiting how much of the network file sharing can consume, they keep the network clear for legitimate, academic uses without blocking particular services or directly monitoring students.
At Harvard, for instance, movie clips needed for classes move unimpeded, but KaZaA files are slowed down. A movie that used to take five minutes to download now takes all night, Crawford said.
But few believe it's making a big dent, and universities are under more pressure to police file-sharing.
Schools are also acting in their own interests. Without tough measures, networks would grind to a halt, impeding academic uses like exchanging databases between researchers.
It was on college campuses - where cash-starved, music-loving students found ultra-fast networks - that file-swapping first caught fire with Napster.
But Napster's demise from a copyright lawsuit only unleashed a flood of other services that trade not only music but TV shows, movies and even computer software. Usership of KaZaA quadrupled in the past year to more than 9.4 million, according to comScore Networks Inc., which measures Internet traffic.
Harvard used to get three or four complaints a year from the industry about activity on its network; now it investigates 25 a week.
Universities say they go after abusers and abide by legal responsibilities to cut off service to repeat offenders.
Northeastern University in Boston offers offenders a daily class on responsible computing - a kind of cyber-detention, said Bob Weir, vice president of information services at Northeastern University.
Still, universities don't want to alienate students by cracking down too hard, and in many places the rules have been kept deliberately gray.
"Our philosophy is as long as students aren't doing something that's damaging or malicious, try not to restrict them more than you have to," said Jerry Smith, director of information systems at Pittsburg. The school, though, says it will act on reports of illegal behavior.
At Northeastern, the 1,800 students who responded to a recent survey ranked the quality of the Internet connection as their top consideration in choosing housing, ahead of food and roommate.
Nonetheless, many believe that more monitoring is inevitable.
Michael Zastrocky, a former administrator at Regis University in Denver and now an analyst at research firm Gartner, said schools that don't monitor or respond to copyright complaints are subject to negative publicity and even legal action, though their legal vulnerability is unclear.
Some monitoring may already be taking place. Surveying schools nationwide, University of Michigan professor Virginia Rezmierski found extensive evidence of logging by network administrators.
Most of the activity counts as sound network management, she said, but many schools aren't setting up policies to distinguish between analyzing patterns and specific content.
Civil-liberties advocates worry that monitoring obstructs the free exchange of information they consider a basic principle of university life.
Monitoring "chills behavior, and can squelch creativity that must thrive in educational settings," the Electronic Privacy Information Center wrote to university presidents.
Chris Hoofnagle of EPIC said copyright holders are trying to turn universities into policing bodies, a charge the entertainment industry disputes.
"Exactly how universities do this is up to them," said Cary Sherman, president of the Recording Industry Association of America. "We certainly wouldn't be proposing that they invade anybody's privacy."
The industry and schools are on the same side, he said, because both have intellectual property to protect.
So far, education, bandwidth shaping and monitoring have done little to curb piracy. The entertainment industry has cited estimates that as many as 2.6 billion copyrighted files are illegally swapped each month.
A musician himself, Harvard's Crawford has mixed feelings about copyright protections. A jazz and hip-hop fan, he uses the Internet to track down music he can't find elsewhere, and often buys CDs after scoping them out online.
Crawford says he hopes Harvard won't get too intrusive, but acknowledges its dilemma.
"I'm glad I'm not in that position," he said.