WALNUT CREEK, Calif. - In cyberspace, anyone can get spammed. Just ask Rush Limbaugh.

The talk-show host recently checked his online mailbox and found it was full of messages from electronic mailing lists. He cleared out the mailbox, and it was full 30 seconds later. Then he cleared it out, and it was full again. And again. And again.

Limbaugh discovered someone had arranged for him to subscribe to hundreds, maybe thousands, of Internet e-mail lists called listservs. The prank crammed his mailbox with computer-delivered electronic junk mail that in Internet-talk is called "spam." And Limbaugh was deluged with more bytes of spam than his system could digest.

"I was put on every stupid listserv out there," Limbaugh told his national radio audience. He even got messages from a listserv focusing on the topic of Sanskrit as a third language.

The radio-and-television personality speculated he might have irked some Internet devotees with his occasional comments about online "low-lifes" who engage in name-calling, insults and verbal assaults during virtual debates.

"Imagine 10,000 letters to the editor every day in your (real) mailbox," Limbaugh said. "This goes to show how widespread this Internet thing is."

The incident also shows how easy it is to play pranks in cyberspace. From hackers to tricksters, the Internet is a kind of electronic Wild West with loosely defined rules, or "netiquette," that are constantly evolving.

"It's pretty easy to make your life miserable online," said Tim Bajarin of Creative Strategies, a Silicon Valley market researcher. "This is just part of the electronic age. If somebody knows what to do with electronic distribution of information, they can have a heyday. Communications technology can be used for good, but it also has an evil side."

For example, listservs are popular ways to receive online letters written by people with interests that match yours, and as such, are deemed a valuable way to communicate.

The Limbaugh incident wasn't the only spam in recent weeks. The e-mail boxes of President Clinton and House Speaker Newt Gingrich and dozens of others were inundated with junk mail.

"This is no different in spirit than having 500 pizzas delivered somewhere or signing up somebody for 300 magazines," said Daniel Dern, a Newton Center, Mass.-based analyst who is a self-described Internet curmudgeon. "It's a form of forgery."

Internet watchers believe this kind of online nastiness could become more widespread. Internet users can use special software to automatically cancel unwanted subscriptions. But this isn't a completely satisfactory means of protection.