AOL executives could not be reached for comment.
The move opens the software up to improvements from anyone who wants to contribute to the project. With a growing pool of developers looking to distinguish themselves by contributing to open-source efforts, that could potentially open the AOL effort up to the same swift debugging and improvement from which Linux has benefited.
However, opening up source code isn't a guarantee for better software. Mozilla, Netscape's open-source project for its Web browser, has been an effort dominated by programmers already on the company's payroll with relatively few others contributing their expertise.
If a person visits AOL's Web site, a copy of AOLserver will deliver the Web page to the visitor's browser. AOLserver powers AOL's main Web site as well as the individual Web sites of all its members. In addition, AOLserver dishes out each advertisement on the site, the company said.
In the past, AOLserver has been available for free, but not the source code, which basically is the blueprint for the program.
The move also is another indication of the increasing comfort among corporations with the concept of open-source software, which is dramatically different from the proprietary philosophy that is more dominant in corporations today. Increasing numbers of companies are warming to open-source software, including SGI and Apple. And some companies, such as Linux seller Red Hat, have bet their entire business on the open-source movement.
Open-source advocates applauded AOL's move. "It's a good thing," said Roy Fielding, chairman of another open-source Web server project, the Apache Software Foundation. As one of the key developers of the HTTP language that Web servers use to transfer information, he can test the latest versions of HTTP with the server software.
AOL joined with MIT's Laboratory for Computer Science to coordinate future development of the software. The software is released under the AOLserver Public License, which is based on version 1.1 of the Mozilla Public License.
Because of the way the Mozilla Public License works, it would be possible but awkward to include any features from AOLserver in Apache, Fielding said. However, to his knowledge, Apache doesn't lack any features that AOLserver has, he said.
AOLserver was trimmed down and several features were removed before it was released as open source, according to developer George Nachman. The reason for the slim-down: the development team wanted a foundation that was faster, more secure, and less likely to crash, Nachman said.
"I believe that the server can now do a great job at a reasonable number of tasks rather than an OK job at a huge number of tasks," Nachman said.
AOLserver's roots lie with NaviSoft, a company AOL bought in November 1995.
Open-source software is becoming better accepted in the commercial world, Fielding said.
"There is more commercial involvement in open-source software. They're not just using it but helping to develop [it]," he said. "That's a very welcome change from the past."
Part of the reason for the acceptance is that open-source software gives companies control over new features and bug fixes that otherwise would be left in the hands of the software developer, such as Microsoft or Netscape, Fielding said.
Next to Linux, Apache is probably the most successful example of open-source software. The Apache Web server powers 56 percent of publicly accessible Web servers on the Internet, according to a Netcraft survey. IBM has included Apache in its own Web software tools.