A Novell-led fork of OpenOffice.org that was actually shipped as 'OpenOffice.org' by most Linux distros. Go-oo added VBA support and OOXML features but was controversial for its Microsoft ties. It was absorbed into LibreOffice in 2010.
Go-oo was a patchset and build system (ooo-build) applied to OpenOffice.org source code, adding VBA macro support, OOXML import/export, performance improvements, and additional language support. It also used the system's native libraries where possible rather than OpenOffice's bundled versions.
Go-oo is the fork that most people never knew they were using. Starting in 2003 as a patchset maintained at Ximian (later acquired by Novell), it grew into a full distribution that was shipped as 'OpenOffice.org' by most major Linux distributions — even though it wasn't the official OpenOffice.org code from Sun Microsystems.
The fork existed because Sun was notoriously slow to accept patches from outside contributors, even corporate partners. Go-oo maintained a growing set of patches that included performance improvements, additional file format support, and features that Sun refused to integrate. The first standalone release was Go-oo 2.3.0 in October 2007.
But Go-oo was deeply controversial. Its Novell sponsorship raised eyebrows after Novell's 2006 patent agreement with Microsoft. Critics alleged that Go-oo's inclusion of Visual Basic for Applications (VBA) support, OOXML file format compatibility, and use of the Mono framework were part of Microsoft's strategy to extend its influence into the open-source office suite ecosystem. Sun's Simon Phipps called it 'a hostile and competitive fork.'
The irony was thick: the 'official' OpenOffice.org that most Linux users ran was actually the 'unofficial' fork. Go-oo was what users wanted; Sun's version was what Sun wanted.
When Oracle acquired Sun in 2010 and the Document Foundation launched LibreOffice, Go-oo's developers and patchset were immediately absorbed. Go-oo's years of accumulated improvements became part of LibreOffice's foundation, and the fork ceased to exist as a separate project. In a sense, Go-oo didn't die — it metamorphosed into LibreOffice, bringing its controversial but useful features along.
Go-oo is technically a 'merged' fork, but the story belongs in a discussion of fork drama because of its years as the secret fork that dared not speak its name.
ooo-build patchset started at Ximian
Novell-Microsoft patent agreement raises suspicions about Go-oo's motives
Go-oo 2.3.0 released as first standalone fork
Most Linux distributions ship Go-oo as their 'OpenOffice.org' package
The Document Foundation announces LibreOffice; Go-oo merged immediately
“We ship what users actually need, not what Sun's copyright assignment process allows.”
Go-oo demonstrated that forks can exist in plain sight for years, disguised as the original. Its patchset became a core part of LibreOffice's DNA, meaning that many of LibreOffice's advantages over OpenOffice trace back to Go-oo's years of independent development. The Microsoft/Novell controversy also showed how corporate politics can taint an otherwise beneficial fork.