Company says it paid for the code that was contributed, against contract, to free Mambo publishing software.
Brian Connolly, president of Chicago-based Furthermore, plans on Monday to distribute broadly a warning that asserts that users of some Mambo features "are potentially exposed to civil litigation and possibly criminal prosecution" because of copyright infringement. In a rebuttal, Mambo programmers deride the claim as "frivolous and without substance."
In an interview Thursday, Connolly said he contracted with one of Mambo's core programmers to write a proprietary module that plugs into Mambo, but that programmer contributed the modules to the open-source project against the terms of his contract.
The module, called Lead Story Block, is one of several features that make it easier to use Mambo to build Web sites that look like newspaper sites. Furthermore, which is part of software company Literati Group, is trying to start a business hosting such Web sites, Connolly said.
The dispute is the newest chapter in the sometimes awkward interface between the open-source programming philosophy and intellectual property law. The former encourages unfettered sharing of software, but the latter is geared toward restrictions that help individuals or companies keep control over their technology.
The most prominent case featuring a clash of open-source and proprietary methods is The SCO Group's legal case that argues IBM violated its contract with SCO by moving proprietary Unix code to open-source Linux, but there have been others. And in another case, a Dutch company called Sitecom tangled with a programmer of the open-source netfilter/iptables networking software, which was used in a Sitecom networking product.