Mozilla 1.0, the open-source technology behind the latest Netscape browser, is garnering favor for helping to block irksome pop-up advertisements. But don't expect to see that feature in the coming full release of Netscape 7.0. Mozilla 1.0, launched in early June as the first public version of the Netscape-inspired open-source browser, lets Web surfers easily zap unsolicited windows known as pop-up ads, which are widely used by mainstream sites including America Online and its subsidiary Netscape Communications. Though heralded by Mozilla users, a group that includes many Web developers, the tool didn't make the cut for the preview version of Netscape 7.0 and won't appear in its upcoming launch, according to the company.

That arrangement, analysts say, is blatant self-protection. "Netscape is a commercial offering--it's not in its interest to offer a browser that could kill pop-up ads," said Michael Gartenberg, research director with Jupiter Research. "That's the equivalent of one of the broadcast networks coming out with a digital video recorder that can skip commercials."