Students tired of Viagra ads, get rich quick schemes and provocative offers from “the girl you met last night,” have a new weapon in the war against spam.

A filtering service for Harvard e-mail addresses was released on the Harvard Arts and Sciences Computer Services (HASCS) website last week in response to consistent requests from students and staff.

The tool, called “SpamAssassin,” screens incoming e-mails for specific terms—such as “click here” and “pennies a day”—identified as common in unsolicited commercial messages. If the message has enough flagged terms, it is labeled as spam and can be redirected into a separate folder for users to weed through at their pleasure.

This form of filtering is one of the less-obtrusive methods of preventing spam because it avoids misidentifying legitimate e-mail more so than many other programs, according to Coordinator of Residential Computing Kevin S. Davis ’98.

“There’s always a trade-off between having a lot of spam and having a lot of false positives,” Davis said. “In our environment where people need to get messages quickly, it’s better to err on the side of picking up less spam, and getting legitimate mail.”

While Webmail currently has a feature to blacklist certain e-mail addresses identified as spammers, SpamAssassin can be used with the Eudora and Pine e-mail clients as well.

Preventing spam consistently ranks as a top concern for Harvard e-mail users, Davis said—especially first-years, who sometimes find spam in their mailboxes the first time they sign on.

“It’s a much demanded option,” Davis said. “Any e-mail address out there these days gets spam.”

Because there are currently no federal regulations against unsolicited commercial e-mail and spamming software is easily available and affordable, the problem is on the rise, Davis said.

“It’s just an ongoing war to stay ahead of spammers,” Davis said.

SpamAssassin has been successfully used at a number of other universities and corporations, and can be turned on at the HASCS website or by typing “blockmail” at the fas% prompt.

—Staff writer Katharine A. Kaplan can be reached at kkaplan@fas.harvard.edu.