But the study, which analyzes the installed base of Web browsers through the end of 1997, shows that Netscape held on to its majority share. And analysts note that the company can boast significant measures to boost its position since the study was conducted.
"It's clear that Netscape has lost market share, but they're still in the lead, and that's an important place to be," said Joan-Carol Brigham, analyst with International Data Corporation, which released the study. "It's also important to note that these numbers are relevant to the period before Netscape started giving its browser away."
Netscape in recent months has cited internal research showing its market share has stabilized in the mid-50s since the beginning of the year.
The IDC report, which measures the installed browser base as of year-end 1997, showed that Netscape's Navigator browser slipped to 50.5 in 1997 from 54.6 in 1996, bringing Netscape to the brink of the psychologically important line between holding a majority and a plurality lead. But even so, Netscape's Navigator browser still has double the share of Microsoft's Internet Explorer, which rose to 22.8 percent from 16.4 percent from 1996 to 1997.
America Online's browser, based on Internet Explorer, rose to 16.1 percent in 1997 from 13.1 percent in 1996. Remaining browsers combined fell to 10.6 percent from 15.9.
Microsoft gained on Netscape last year in four out of five market segments.
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In the medium- to large-business sector, Netscape held its own while Microsoft gained 4 percent. Microsoft gained almost 20 percent in the government market, where Netscape maintained its lead despite losing about 8 percent. Netscape also maintained its overwhelming lead of about 75 percent in the educational market, despite Microsoft's inroads: IE's share rose to 10 percent from 4 percent.
Netscape did best in the small-business segment, where it rose to 46.7 from 44.4 over the year. Microsoft also rose in that segment, to 26.7 from 18.5.
The findings released today essentially present a snapshot of a period that Netscape has put behind it.
Up until the end of last year, Netscape charged for its browser, while Microsoft offered its browser for free. At that time, Netscape followed Microsoft's lead in offering Communicator, its Web software suite that includes the Navigator browser, free of charge.
The company went one step further and released the suite's source code to Web development community and created the Mozilla.org organization to guide that community's work using Communicator code.
IDC's study of the first half of 1998 will gauge the impact of Netscape's strategic moves, said Brigham. That study is due by the summer's end.
Netscape has deemphasized the browser war, attempting to get out of Microsoft's way by focusing on its software products for large enterprises as well as on its Netcenter portal site of services and search for home and business users. But the substantial financial success of Netcenter has come largely from its browser dominance, which has made that portal the default start-up page for Navigator's tens of millions of users.
And while the company's focus on Netcenter may be part of an attempt to take a path other than that of Microsoft's, the giant is coming right back after Netscape with its own entry in the portal arena, Start.com.
But despite Microsoft's continued inroads on browser market share, Brigham said Microsoft's late portal offering would not pose a significant threat to Netcenter for the foreseeable future.
"Netscape is way out ahead of Microsoft," Brigham said. "It's typical of Microsoft to mirror a successful strategy, but the trick is putting some kind of creative twist on it that will keep people coming back. Even if people get there because of the default setting on their browser, it ultimately comes down to how good the portal site is."
In addition to measuring market share between the competing providers, IDC's study also showed that people increasingly are using their browsers for more than just Web surfing. The proportion of people starting up their browsers to purchase goods and services rose to 37.4 percent in 1997 from 30.3 percent in 1996. Those using the browser for scheduling rose to 28.7 percent from 11.6 percent over the same period. And those using it for document management rose to 31.9 percent from 21.1 percent.
The report also forecast an astronomical rise in the overall installed base over the next several years. In 1997, that number was 46.7 million. IDC predicts it will reach 73.6 million this year, 113.1 million in 1999, 160.5 million in 2000, 219.2 million in 2001, and 343.6 million in 2002.