Open source business model 1: Work with friends
Many open source projects are pure hobbies that join together groups of friends. Everyone is a programmer or at least proficient with software. Most people are solving problems they have -- scratching a proverbial itch -- so they're well engaged and rewarded for their time.
The results are rarely polished enough for nonprogrammers, and documentation is often either missing or not current with the latest version. But this economic model still serves the programmers well: They can take the code and incorporate it into their own work, producing new software for their clients or bosses. Eben Moglen, a lawyer who helped Richard Stallman draft the General Public License (GPL), says that open source software packages "provide cheap raw materials."
Everyone is a first-class citizen with all of the privileges of ownership. The participants can profit whenever they find the ability to sell the service, not the code. There's no overhead, no accounting rules, and no battles over intellectual property because everyone shares the title.
Open source business model 2: Work with colleagues
Some of the most sophisticated tools link professional colleagues at different companies with the same job. This model operates much like the one linking friends, but it connects colleagues instead.
The Apache Web server, for instance, was nurtured by a group of programmer who sold Websites and decided to build something that was easy to configure and extremely thrifty with clock cycles. The Apache project now includes millions of lines of code built and used by programmers.
Likewise, Lucene is often found in the back end of Web servers everywhere. The Commons tools are part of many Java stacks. All knit together the contributions of programmers so that other programmers can benefit.