Both Opera Software, a Norwegian browser maker, and NeoPlanet, a contributor to Netscape's Mozilla open source development group, are making aggressive moves just as many see America Online subsidiary Netscape in a newly vulnerable position. NeoPlanet chief executive Drew Cohen said Wednesday that his company plans to release a Mozilla-based browser in February that will compete with Netscape's newest browser, also built on Mozilla code. Cohen drew a sharp competitive line between the two products, calling the recent release of Netscape 6 "premature" and raising concerns that such a release could give Mozilla "a bad name". Netscape could not immediately be reached for comment. Meanwhile, Oslo-based Opera Software on Wednesday began offering a free version of its browser, provided that consumers accept an advertising window within the browser's interface. To eliminate the ads, users can pay a $39 (about £27) registration fee. The move could make Opera, which holds a tiny fraction of the browser market, more competitive with Netscape and Microsoft. With some consumers rejecting the Netscape browser as not ready for prime time, Opera could prove to be an increasingly viable alternative for those who don't want to use Microsoft's Internet Explorer. Microsoft gave away its Internet Explorer browser from the outset, helping it make quick advances on the market. Netscape was compelled to follow after seeing its once-commanding market share shrink in the face of Microsoft's onslaught. When Netscape succumbed to Microsoft's price challenge, it went one step further, releasing the browser's source code to be developed in an open source environment under the auspices of Mozilla. Mozilla was established to organise a worldwide network of volunteer developers in an attempt to replicate the success of grassroots open source efforts such as those that produced the Linux operating system and the Apache Web server. Software produced through Mozilla was made available for free and licensed use, meaning any developer or company could use the resulting code in its software. But under corporate sponsorship, first by Netscape and then by its buyer, AOL, Mozilla found most of its development resources coming from its own paid engineers. Among the outside developers, one of the most active was browser maker NeoPlanet, which paid half a dozen of its engineers to work on the project. After more than two years of development, Mozilla is starting to bear fruit in the marketplace, with Netscape 6 coming out last month. Mozilla isn't scheduled to release its own version 1.0 browser until the second quarter of 2001. Now, NeoPlanet is preparing to offer its first Mozilla-based browser. The company will release a "beta", or trial, version the first week of January and a final version around the end of February. January's beta won't be NeoPlanet's first Mozilla-based release. In April of last year, the company put out one of the first implementations of Mozilla code, a technology preview of its browser using Mozilla's rendering engine, Gecko. The rendering or browsing engine handles the core Web browsing responsibilities of displaying text and images on a computer. NeoPlanet's new release will be its first fully Mozilla-based browser. Prior versions required Internet Explorer components. NeoPlanet will also expand its pool of paid Mozilla contributors from six to nearly a dozen. Cohen said Netscape released its new browser before Mozilla bug squads had time to iron out key problems with the code. "We think Netscape released 6.0 early," Cohen said. "I expected them to wait until [those bugs] were fixed. We talked long and hard internally about trying to release at the same time Netscape did, but ultimately we decided it wasn't as important to release when they did as it was to create a great product that was ready for users. "We want Netscape 6 to be successful," he added. "So I wish they had waited, too. We don't want Mozilla to get a bad name." Take me to ZDNet Enterprise Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read what others have said.