Microsoft may be forced to compete in the Web browser industry once again, as alternative browsers grow more popular, threatening its online hegemony, warned Netscape Communications co-founder, Marc Andreessen.

The success of alternative browsers such as Mozilla Foundation's Firefox may cause Microsoft to be more aggressive in leveraging its dominance of Internet client software, he said.

After Internet Explorer (IE) surpassed Netscape as the dominant Web client, browser innovation at Microsoft "pretty much stopped in 1998," Andreessen said during a session at the Web 2.0 conference in San Francisco Wednesday. This means that the company has not done all it could have done to use the browser to strengthen its other products, such as its MSN service, or to prevent competitive Internet companies such as Yahoo from growing, he said.

"One of the most amazing things over the last six or seven years is watching Microsoft basically get a monopoly over the browser and then not use it," he said.

Microsoft's market to lose

Internet Explorer has been used by approximately 95 per cent of Web surfers since June 2002, according to WebSideStory analysts. Recently, however, its dominance has begun to erode slightly, due in part to a number of well-publicized IE security vulnerabilities and a generally favourable reception to Firefox, a slimmed-down browser developed as part of the open-source Mozilla project.

Increasing pressure from alternative browsers such as Firefox and Opera will ultimately cause Microsoft to take a second look at the browser and how it can better be used to leverage Microsoft's monopoly, Andreessen said.

"Microsoft is certainly going to respond competitively to these things. I can guarantee that," he said. "I think that it is quite possible that this is going to get very interesting over the next two or three years," he said.

Changing times

Andreessen's comments came during a discussion with Yahoo chief operating officer Dan Rosensweig, in which they discussed the future dynamics of the Internet business. Andreessen is also co-founder and chairman of Opsware.

The two were disagreed as to whether control over user data would become a major issue in the coming years, with Andreessen arguing that denying users control over their data ultimately would be a way of locking customers into "walled gardens" of Internet services.

The phenomenon can already be seen with companies such as eBay, he said. "You can't get your reputation out of eBay, you can't get your purchase history out of eBay, you can't get your stores out of eBay," he said. "It's a plantation owner/sharecropper kind of relationship."

Rosensweig, whose company has more than 150 million registered users, argued that consumers today have retained the ability to change their online habits. "We noticed a few people who changed their habits in the last few years in some categories," he said. "Search may be one."

"We're living in a world today where it's too easy to change."