You probably found yourself annoyed by one before you came to this very Web site.

Those ubiquitous X10 Web-cam ads that pop up incessantly as you try to view the day's news or buy a gardening book seem to be taking over computer desktops everywhere, driving Webheads and newbies alike mad.

"So Tiny It Fits Anywhere: Front Door, Office, Nursery, Garage, Web – And More!" the ads practically shout, alongside a photograph of an attractive young woman in a come-hither pose.

"They’re a nuisance," said Jason Fox, managing director for production at Columbia Digital Knowledge Ventures, an arm of Columbia University. "They're very creepy, and they're slightly pornish. Everyone finds them very obnoxious."

The so-called "pop-under" ads open up underneath rather than over the top of existing Web pages, and therefore don't interfere with the ability to read what's on a Web page. But they do open up another browser icon, which invariably leads Web users to click on to investigate.

Because of that, X10’s Web-cam advertising is the fifth most visited Web site in the Internet for May, according to Internet tracker Jupiter Media Metrix. Nearly 30 million unique visitors went to the site – or, rather, the site went to 30 million unique visitors.

And that’s the problem. Seattle-based X10 Wireless Technologies might be basking in its success at a time of general dot-com gloom, but observers see it as the equivalent of Internet telemarketing.

"They’re like drive-by shootings," said Kipp Cheng, interactive news editor at Adweek. "Consumers will not put up with that."

They’re also in extremely poor taste, according to some Internet users.

The Los Angeles Times’ Web site, Latimes.com, reportedly asked the Web-camera retailer to create ads that would be more "tasteful." Previous X-10 ads suggested the small cameras be placed in the bedroom, along with encouragement to use them for security purposes as well as for "fun" and "candid camera parties."

And the models in the ads were usually in semi-reclining poses, draped over couches in a way that didn’t bring home-security issues to mind.

X10 President Alex Peder did not return a call for comment, but the X10 Web site offered a statement on the ads.

"A few years ago, the standard 468x60 'rectangle' ads at the top of Web sites were very new. Many people were uncomfortable with these ads but with time, people got used to the ads," it read. "X10.com is simply using a new form of advertising. Please try to understand that this type of advertising is what keeps the Internet enjoyable as it pays for operational costs behind the sites you enjoy visiting for free."

And New York Times Digital senior public-relations manager Christine Mohan said not all the feedback the newspaper's Web site was getting about its X10 ads was negative.

"They did say it wasn’t interfering with viewing of the (nytimes.com) content, that it was not as intrusive as perhaps a pop-up," she said.

Not that there haven’t also been people who were less than happy with the pop-under ads, which on the Times Web site are also being used for advertisers Iwin.com and Half.com. But weighing the complaints and the kudos are all part of what goes into figuring out what makes something no one’s quite figured out yet: the perfect Internet ad.

"We definitely want to look into new technologies, but it’s that fine balance you want to reach to be introducing new things and flexible for the advertiser while maintaining a good user experience," Mohan said.

Nytimes.com puts a once-a-day cap on how many times a pop-up or pop-under ads show up while a user’s browsing the Grey Lady online. Those users who do find the ads irritating are directed to www.x10.com/x10ads.htm, where X10 Wireless Technologies offers a link that will banish the pop-unders from your computer for 30 days at a time.

Other, more lasting ways to stop the pop include downloadable software such as PopNot (www.hdsoft.com/popnot) and AdSubtract.(www.adsubtract.com), which create filters that catch the ads before they appear on a computer screen.

Cheng doesn’t predict the pop-unders will be bothering Internet users for long, though. He sees them more as a symptom of the general poor state of things in the dot-com world, where, compared to the flush 2000 age, Web sites are scrounging for any revenue they can get. Web sites typically charge advertisers by the cost per thousand, or CPM, meaning the price tag for every thousand Internet users who see the ad. In 2000, he said, the price was somewhere around $85. In 2001, it’s been about $1 or $1.50.

"The prices of CPMs haven’t been sliding, they’ve been plummeting," he said. "And … because CPMs are going so crazy, you’ve got all this crappy advertising, the bottom of the barrel coming out."

Because the pop-up ads are so annoying, he said, advertisers are going to learn that using them could hurt them more than help them. There’s a parallel in the real world with most retailers, who figured out that the way to sell a vacuum cleaner or a Lexus isn’t by going door-to-door or calling up strangers at dinnertime.

"The majority of people don’t respond to direct-mail pieces and telemarketing," Cheng said. "All this with the pop-up windows will eventually go away."