Google's pop-up blocker, included as part of the Web search engine's popular browser plug-in, "worked fantastically well for about two months, blocking everything," said Haigh, a photographer from the United Kingdom. "Then the odd pop-up started to appear, mainly on highly ad-displaying sites based in the United States."
"I know they are on the increase because they are annoying me again," he said, adding that he's received three this week.
Pop-up purveyors are finding ways around popular new filters that aim to stomp them out, the latest sign of an Internet arms race over one of the most controversial online ad formats around.
At stake is the future of a lucrative form of online advertising that many ad executives say is among the highest performers for Internet marketers--despite severe negative reactions from a majority of Web users.
Pop-up purveyors are finding ways around popular new filters that aim to stomp them out, the latest sign of an Internet arms race over one of the most effective and controversial Web advertising formats around.
Google, America Online,, EarthLink, Microsoft and a slew of developers have begun offering consumers easy-to-install, . As much as 30 percent of the Internet population uses a pop-up guard, according to estimates from ad technology companies. That number is set to soar when Microsoft releases an later this summer that is expected to include a pop-up blocker for its Internet Explorer Web browser, which serves about nine in 10 people who surf the Web.
Because IE so thoroughly dominates the browser market, ad executives and Internet watchers could finally burst the bubble for pop-ups.
But marketers intent on preserving and extending the lucrative format have already developed workarounds that are duping existing blockers, setting the stage for a major battle for control over consumer PC screens.
"Relatively quickly (IE) will displace all other pop-up blockers, then people will try to figure out how to get around that," said Richard Smith, a privacy and security expert.
At stake is the future of a form of online advertising that many ad executives say is among the highest performers for Internet marketers--despite severe negative reactions from a majority of Web users.
Research shows the ads have only become more predominant since the rise of pop-up guards. In the last two years, the number of pop-ups and pop-unders delivered to Web users has more than tripled. (Pop-ups appear over a Web page, while pop-unders appear behind one, but otherwise they function the same way.) They made up 6.4 percent of all online ads in April of this year, compared with 1.8 percent in the same period of 2002, according to data from researcher Nielsen NetRatings.
Publishers willingly allow pop-ups or pop-unders because they command higher prices, and they're in high demand by advertisers. Ad executives say they can cost advertisers about $10 per thousand sent for top-rated sites. That compares with between $2 and $3 per thousand for a static banner ad that appears on the same popular site.
The Web sites that sold or disseminated the most pop-up ads in the month of April include CNN.com, ESPN.com, Excite.com, Weather.com, and The New York Times.
Click rates, or the number of times people click on an ad, could explain the growth of pop-up ads. Marketers say between 2 percent and 5 percent of the people who receive them will respond with a click. That compares with less than 0.35 percent for the most widely used ad on the Net today, static banners, according to an ad server report from DoubleClick.
"Pop-unders still yield the best performance," said John Enghauser, business development manager for TrafficMarketplace, an ad network and one of the biggest distributors of pop-ups. He said that his company does not do any workarounds to deliver the ads.
Blocking software typically suppresses a new window. It detects a command known as "openwin" for opening a new window, which would be written into the HTML (Hypertext Markup Language) of a Web page. That command calls on a third-party server to deliver the pop-up or pop-under.
Deflating pop-up blockers
Some new pop-up techniques simply avoid that command, thus subverting blockers that rely on suppressing it. For example, some advertisers are sending pop-ups through a "user initiated command" triggered when people mouse over an object on the page, according to ad executives familiar with the technique.
The pops don't stop
Despite a rise in software to block pop-ups and pop-unders, the intrusive ads have more than tripled their online presence in the last two years.
Share of online
ad market (percent)
Source: Nielsen/NetRatings AdRelevance
Mainstream advertising networks and distributors are reluctant to discuss what steps, if any, they are taking to circumvent pop-up blockers, although some admit that they've developed new methods to serve such ads. In addition, some advertisers are busy developing intrusive formats that mimic pop-ups in their ability to grab attention, but that don't surrender control over when and how they're displayed to consumers' Web browsers.
Publishers have taken to spawning in-pages ads in lieu of pop-ups, called "overlays" or "floater ads." Like stacking paper, the ads will float over the middle of a Web page to catch people's attention before reading requested content. Visitors typically can't manipulate the ads like they can a pop-up or pop-under by minimizing the window or clicking the exit button. Floating ads will remain on the page until they disappear, or until the visitor leaves the page.
Pop-up blockers like Google's or Yahoo's don't prevent these ads from appearing because they use a different command.
Floating ads appear because they're written in coding language called dynamic HTML, which contains a series of embedded commands that ad blockers typically don't block.
Sites including Netscape and MSN Money use overlay advertisements in lieu of pop-ups.
Many ad-delivery companies are now using technology to detect whether or not a computer or visitor has installed a pop-up blocker. If one is detected, it will deliver a floating ad to the page instead. Burst Media, for example, is one company that is experimenting with the overlays.
"Instead of a pop, they float over the page," said Jarvis Coffin, CEO of Burst Media, which represents ad sales for about 2,000 sites.
Undertone Networks, one of the largest distributors of pop-under ads, with customers including Yahoo Personals, HBO and Orbitz, uses pop-up blocking detection technology from Zedo, an ad delivery company based in San Francisco.
Yahoo spokeswoman Stephanie Iwamasa said that because the ads are delivered differently, the company doesn't necessarily consider them pop-ups and therefore doesn't block them. However, she said, Yahoo is always evaluating new technologies to help improve consumers' experience on the Web.
Pop-ups came into fashion during the dot-com bust, when publishers were desperate for ad dollars and sought to please marketers with more attention-grabbing means to reach consumers. But Web surfers came to loathe them, and publishers such as the Web site for The New York Times moved to regulate how often people receive them.
Downloadable software to block the ads also has become ubiquitous; major Internet service providers, software companies like Panicware, and even Amazon.com offer tools to staunch them.
Yet it remains to be seen whether they will die out now that the overall Internet advertising industry has rebounded. Last week, the trade group Interactive Advertising Bureau reported a record quarter of sales for the industry, the in 1996. Sales for the first three months of 2004 were $2.3 billion, up from $1.6 billion in the year-ago period.
Jason Krebs, head of online ad sales for The New York Times' Web site, said that the online newspaper continues to sell pop-unders as one of many options because they're effective for advertisers. He added that he has no problem with blocking technologies from Google and others.
"You cannot stop technologies. What we do is we adapt to the changing technologies (and advertising environment) and continue to operate the business successfully," Krebs said.