If you think you're seeing more unsolicited commercial e-mail, jokes and chain letters than you did last year, your hunch is right, according to researchers and Internet security experts.

They say spam - the generic term for these annoying messages - increased to somewhere between 30 percent and 50 percent of all e-mail in 2002.

Most of it appears to be annoying computer users through their personal e-mail. A survey by the Pew Internet & American Life Project found that people who use e-mail at work don't feel particularly overwhelmed by either spam or a torrent of legitimate messages. In fact, American workers often find e-mail at work a respite from the spam assault on their personal accounts.

The content of spam also may surprise some of us. While ads for pornography sites and sexual aids grab the public's attention, the largest single category of spam, 32 percent, is financial in nature, according to Brightmail Inc., an anti-spam technology company that tracks the flow through its Probe Network.

These include mortgage offers, debt consolidation, insurance pitches and schemes for making thousands of dollars working from home on your computer.

Most efforts to combat spam have revolved around technology - software that tries to filter out spam at the server level (before it gets to users) or on individual desktops. A handful of companies and individuals also have sued and won judgments against spammers in states that permit lawsuits.

In October, for example, America Online won a $7 million civil judgment against a spamming ring in U.S. District Court. But in the absence of strong legislation, the spammed rarely wind up collecting on those judgments.

In May, the European Union practically outlawed spam, making it illegal to send unsolicited commercial e-mail to someone unless there is a pre-existing business relationship. Efforts in the U.S. Congress to ban spam have fizzled over the years.

Although spam may not appear as dangerous as computer viruses, unwanted e-mail is a daily nuisance, requiring users to spend inordinate amounts of time sifting through junk to find legitimate messages, said Mark Sunner, chief technology officer for MessageLabs of Gloucester, England, which filters e-mail for international business clients.

MessageLabs, another anti-spam firm that tracks unwanted e-mail through its clients, said in its annual report that one in every 212 messages contained a computer virus this year, compared with one in every 380 the year before.

Even more ominously, MessageLabs says that one in every three e-mails its clients received this year was spam, and that it expects the volume of spam to overtake legitimate messages in 2003.

Analyst James Kobielus of the Burton Group says a convergence of trends has set the stage for the onslaught of spam.

One trend, he says, is the ubiquity of e-mail. Once spammers have your address, they can send you e-mail from almost any system in the world. Meanwhile, the Internet has become an important part of our lives, and e-mail is its most popular service. In addition, individual addresses are available in many places on the Internet - even if they're not on a list purchased by a spammer.

Kobielus says that for the spammer, spam must be working - otherwise there wouldn't be so many spammers. For example, spam might be the only real way to extend the audience of a pornographic Web site. Most porn operators can't place ads in magazines and newspapers, or on billboards.

By conventional advertising standards, spam costs almost nothing. And, while most recipients may ignore the spam that comes their way, some not only open it - some also respond to the spammer.

"These people wouldn't do it if it wasn't effective," Kobielus said. "Someone is making money off of it."

Although much of the anti-spam effort is generated by businesses, Lee Rainie, director of the Pew Internet & American Life Project, a nonprofit, independent think tank that looks at the social impact of the Internet, said a recent survey of workplace e-mail users shows that they aren't overwhelmed by it.

He offers a couple of explanations. First, spammers may have more trouble obtaining business e-mail addresses than they do personal addresses. Although high-tech workers may have their e-mail addresses posted everywhere, the average American worker in the back room of a company with its own e-mail server is less exposed than e-mail with personal addresses on AOL, MSN Hotmail or Yahoo!

For example, spammers target AOL users with programs that create logical permutations of thousands of common names that can be attached to "@aol.com" to create a mailing list. Only a fraction might be deliverable, but on a service with 32 million customers, that's still plenty of hits.

Another part of the equation, Rainie says, is that work e-mail systems are not only hard to penetrate (particularly on systems that filter spam), they have a lower response rate.

"We're not saying everyone should be complacent," Rainie says. "What we're saying is that the reality in the workplace is that people are not getting too much e-mail and not getting a lot of spam."

At home, it may be a different story. Pew hasn't surveyed e-mail users about spam since late 2001 and may do so again in the spring. But the trend was clear even a year ago. "We found that there was increasing irritation about spam, some of which had lapsed into anger," Rainie said.

The Burton Group's James Kobielus said the word needs to get out that there are solutions for blocking spam. For example, desktop programs can help home users, even if they do no more than automatically dump spam into a junk mail folder.

Corporations, of course, can purchase the services of such companies as Brightmail or MessageLabs, who filter e-mail before it gets to the company's server. Or company IT officers can block the e-mail at the company's firewall or mail server, stripping out both spam and known viruses before they reach users.

Some spam fighters say the real cost of junk mail may be psychological.

"One of the emotional aspects about spam is seing the pornography. It's the really strange stuff, from some hidden e-mail address in, say, Korea," says Alexander Eckelberry, president of Sunbelt Software, which sells IHateSpam, a desktop e-mail filter.

"E-mail," he says, "should not be an emotional issue."