Affero: A new GPL for SaaS

The Affero General Public License, a new variation of the seminal General Public License (GPL) specifically for one situation the regular GPL doesn't address, is now final.

The Affero GPL contains a provision specifically for situations when software it governs is accessible as a service over a network. Where the GPL treats that situation as a private use of software, permitting the user to keep any changes private, the Affero GPL lets programmers include a requirement that users of the software must be able to download it when it's offered as a network service.

The Free Software Foundation, the organisation founded by Richard Stallman in the 1980s to bypass the proprietary constraints of the traditional software world, published the new software license Monday after releasing draft versions earlier this year.

The Affero GPL license is increasingly relevant as companies such as Google employ customised open source software to run massive online businesses with no requirement for sharing. However, intellectual property attorney Eben Moglen, who helped craft GPLv3, said other pressure can be brought to bear if companies take advantage of GPL software without reciprocating.

"If you want to protect your business model, you must be model citizens of the environment. If you shrink, political pressure will grow to constrain your rights to secure the rights of everyone else," Moglen said in May. "Upon the behavior of Google much depends."

The FSF had contemplated adding that feature of the Affero GPL to the new version 3 of the GPL, but chose instead to release the separate license. Adding yet another license to the profusion already available to free and open-source programmers complicates licensing choices somewhat, but the FSF said that code written under the GPL and Affero GPL may be combined in some circumstances

The FSF's Affero announcement is available, as is a set of frequently asked questions.