The 800-pound gorillas are signing on to the movement to end one form of annoyance on the Internet — pop-up advertisements. The New York Times reports Time Warner, owner of AOL, and its competing portals, have decided it is time for the weasel to stop popping.

The big ads that flash in separate windows above or below Web pages are among the most intrusive, and to many people, the most obnoxious features on the Internet. Not coincidentally, the pop-up format is also among the most effective for advertisers and the most profitable for Web site publishers.

But the potential reach of these ads is starting to be sharply curtailed as major companies, like Time Warner's AOL unit, Yahoo and Google, distribute software that blocks pop-up ads from opening. This summer, Microsoft will put a pop-up blocking feature in the next release of Internet Explorer, the dominant Web browser.

Earthlink has taken the lead in the backlash, providing pop-up blocking software to its customers.

"There is a consumer revolt as forms of advertising get more intrusive," said Rob Kaiser, vice president for narrowband marketing at EarthLink , the first big Internet service provider to distribute pop-up blocking software. The reaction to pop-ups, he said, is similar to the rush to join the government's do-not-call list to block telemarketing calls and the increase in the use of video recorders to block TV commercials.

I haven't tried Earthlink's blocker, but I do rely on the feature when I am surfing with Apple Computer's Safari, which I use about 80 percent of the time. In fact, it is one of the decision makers in regard to which browser I open. Internet Explorer renders more web pages effectively, but does not block ads. It is also slow compared to Safari and OmniWeb. But, a world in which pop-ups are stymied is not perfect surfdom. There is inconvenience in not having ancillary windows open when signing into a service such as Wi-Fi hotspots or completing forms. Ideally, it would be possible to have pop-up windows without them being taken over by intrusive advertisers.

A shill of the advertising industry says Internet users should appreciate pop-up ads.

"I haven't spoken to any people who say I love pop-ups, send me more of them," said David J. Moore, the chief executive of 24/7 Real Media, an online advertising firm. "But they are part of a quid pro quo. If you want to enjoy the content of a Web site that is free, the pop-ups come with it."