It has been 15 years since Marc Andreessen developed the Netscape Internet browser that introduced millions of people to the Internet.
After its early success, Netscape was roundly defeated by Microsoft in the so-called browser wars of the 1990s that dominated the Web's first chapter.
Andreessen appears to want a rematch. Now a prominent Silicon Valley financier, Andreessen is backing a start-up called RockMelt, staffed with some of his close associates, that is building a new Internet browser, according to people with knowledge of his investment.
"We have backed a really good team," Andreessen said in an interview earlier this summer. A moment later, Andreessen appeared to regret his comment, saying he was not ready to talk about any aspect of the company.
But Andreessen suggested the new browser would be different, saying that most other browsers had not kept pace with the evolution of the Web, which had grown from an array of static Web pages into a network of complex Web sites and applications. "There are all kinds of things that you would do differently if you are building a browser from scratch," Andreessen said.
RockMelt was co-founded by Eric Vishria and Tim Howes, both former executives at Opsware, a company that Andreessen co-founded and then sold to Hewlett-Packard in 2007 for about $1.6 billion. Howes also worked at Netscape with Andreessen.
Little else is known about RockMelt, and Vishria was unwilling to discuss it. "We are at very early stages of development," Vishria said. "Talking about it at this stage is not useful."
After Microsoft defeated Netscape, it controlled more than 90 percent of the browser market. Interest in browsers among technology companies waned and innovation ground to a halt. But in the last 18 months, the Internet browser has become a battleground again with giants like Google, Apple, and Microsoft fighting one another.
The renewed interest in browsers is partly a result of the success of Mozilla, a nonprofit. The speedier, safer and more innovative Mozilla Firefox browser, introduced in 2004, has grabbed 23 percent of the market, and Microsoft's share has dropped to 68 percent.
But the latest battle was also prompted by a giant shift in computing that is increasingly making the Web, not the PC, the place where people interact with complex software applications. Technology giants now see the browser as a control point to what users do online, and they want a say in shaping it.
In the last 18 months, Microsoft and Apple introduced greatly improved versions of their browsers, Internet Explorer and Safari. And Google entered the fray last fall when it released its Chrome browser. Last month, Google said it would build an operating system, also called Chrome, with its principal function being to support its browser.
"The days of working in isolation on your computer are mostly gone," said John Lilly, the chief executive of Mozilla. "Because the Web has become so central to what we do, and the browser is the technology that mediates our interaction with the Web, the way the browser works is really important. There is a lot of room for innovation."
The policy says that a person could use a Facebook ID to log into RockMelt, suggesting that the browser may be tailored to display Facebook updates and other features as users browse the Web. Another browser, Flock, based on Firefox, already incorporates feeds from social networking sites.
But RockMelt is not currently working with Facebook. "We are not aware of any details about RockMelt and its product," said Brandee Barker, a Facebook spokeswoman.
In the interview this summer, Andreessen credited Mozilla with coming up with an economic model to support Web browsers. The organization has an agreement with Google that makes Google the standard home page when people start Firefox, and sends them to Google when they type something into the search box at the top of the browser. In 2007, Google paid Mozilla about $75 million for the alliance.
"Browsers today have a great business model," Andreessen said.
But experts say a big challenge for any new Web browser could be distribution. Despite Google's heavy promotion of Chrome, the browser has gained just 2 percent of the market.
"If anybody could do it today, one would imagine Google would be best positioned, and it is obvious they have made only meager gains," said David Yoffie, a professor at the Harvard Business School, and the co-author of "Competing on Internet Time: Lessons From Netscape and Its Battle With Microsoft." Yoffie said that aiming the browser at Facebook users could be a good strategy.
"If you can get Facebook's millions of users to think that this is a better way to do what they do on Facebook, that would be an opportunity to take advantage of," he said.