Many Yale students know they can use file-sharing software to obtain their favorite music off the Internet. But what they may not know is that someone could be watching them while they do so.

A small London-based company called NetPD has started to track down students who share copyrighted files and is sending letters of complaint to universities, asking schools to take the students off their networks.

“We’ve already received just under 20 letters,” said H. Morrow Long, a Yale information security officer.

Long said that NetPD monitored songs by Michael Jackson and Incubus on the Aimster and Kazaa networks and sent letters to Yale students who shared those songs with other users.

On its Web site, NetPD lists Sony Music Entertainment and the Recording Industry Association of America among its clients. Both Michael Jackson and Incubus are represented by the Sony label.

Students who only downloaded songs by those artists were not caught, however. Only students who uploaded those songs to other users were singled out.

“They’re catching people serving stuff. The only problem is a lot of people aren’t aware they’re sharing all their files,” said Long.

Yale has notified those students mentioned in the letters of complaint, but it has not punished any of them, nor is it currently required to do so. Long would not give the names of the students.

“It’s kind of scary that they can actually see if we’re getting a song off the Net. Of course, I don’t actually download anything illegal, but my friends who secretly like Michael Jackson might think twice next time,” Johnny Lu ’05 said.

At some other universities, officials have received far more complaints. The University of Maryland at College Park has received more than 100 since the beginning of the semester, according to the Chronicle of Higher Education.

Some schools are even considering punishing students caught sharing copyrighted material. At the University of North Carolina at Asheville, officials have proposed banning students from the campus network if they are caught three times, according to the Chronicle.

But the notices sent by NetPD may be nothing more than a scare tactic. Under current law, NetPD must specifically point out that it is an agent of the copyright holders in its notices, as well as leave an electronic signature, or esignature, on the notices, neither of which it currently does.

Ever since the introduction of Napster in 1999, file-sharing across the Internet has been threatening major record labels, forcing them to fight back. Last year, a lawsuit by Metallica caused Yale to ban all campus access to Napster, forcing students to find alternative file-exchange applications. After losing a court battle with the record industry, Napster shut down its file-sharing operations. A statement on the Napster Web site said the company plans to start a revamped service in early 2002.

To fill the void, many new file-sharing programs have surfaced, including Kazaa, iMesh, Grokster, BearShare, Aimster and Morpheus. The Morpheus software is currently the most popular download at download.com, getting over 1.3 million downloads a week.

The new programs go even further than Napster by allowing users to share movies, software and various other files in addition to music.

Use of Napster alternatives is up 492 percent since March. Nearly seven million unique users logged on to music-swapping services in August, according to Jupiter Media Metrix, an Internet research and consulting firm.

The RIAA has not stood by idly and watched this take place. Last month, along with the Motion Picture Association of America, it filed suit against Consumer Empowerment BV, MusicCity Networks Inc. and Grokster Inc., the owners of the file-sharing services Kazaa, Morpheus and Grokster, respectively.