Gabriel Weinberg, founder of search engine Duck Duck Go, isn’t religious, which is one of the reasons he’s comfortable calling his latest project a “tithe,” despite the connotations attached to the term.

Just about every startup on the planet benefits from the use of open source software–everything from database software PostgreSQL to the Apache web server–which is free to use.

Weinberg’s idea is simple: reckons companies that make a profit with the help of Free and Open Source Software should return a tenth of their profit to the open source community, to help solve problems with some open source projects.

For example, the operating system on which Weinberg runs Duck Duck Go, FreeBSD (for those of you who aren’t OS geeks, it’s another FOSS alternative to Mac OS and Windows, like Linux), is not available on Amazon Web Services, the cloud-based computing-on-demand platform upon which many startups rely.

According to Weinberg, this issue has been open for years; it just isn’t a priority for the FreeBSD developer community. “That’s an example where, if the fix were baked into program, it would be immeditaly used by lots of people,” says Weinberg.

In open source projects, the scarce resource tends to be time, but money can help free up the time of a programmer, by providing an incentive to contribute code in off hours, or even to allow a programmer to take time off in order to work on a problem.

That’s where tithing comes in. Weinberg hopes that by setting an example for the community, he might be able to start a trend that all startups will feel some inclination to be a part of. That’s why he’s pledged 10 percent of the gross of the 2010 and 2011 revenue of Duck Duck Go to open source projects, half of which will be chosen by the DDG community.

Two other startups have already followed suit, one of which, SearchForPHP.com, is a vertical search engine devoted to helping programmers find code snippets.

This level of generosity might sound improbable. But, as one commenter noted on Hacker News, there is a precedent in the GNU Manifesto penned by Free Software movement founder Richard Stallman. In this foundational document, Stallman proposed a “software tax” to help pay for ‘free’ software, acknowledging that, after all, programmers have to eat, too.

At least one very public attempt to donate money to an open source project failed, illustrating that open source projects without the administrative resources to effectively distribute money can’t do much with it. Weinberg proposes that one solution to the problem of how to disburse money donated to open source projects would be simply to offer it as a bounty: the coder with the best patch for a particular problem wins a cash prize.

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