SPI Formally Non-Profit
Software in the Public Interest, Inc. is now formally a 501 (c) (3) non-profit
organization, meaning that all donations are now tax deductible. SPI is the
umbrella organization of several free software projects, primarily Debian, but
also GNOME, Berlin, and the Open Hardware project. They (Disclaimer: I am
a Debian developer, and thus associated with SPI) claim to hold the Open Source mark.
The poster is correct that, according to the USPTO database, the application for a federal registration of OPEN SOURCE as a certification mark of software licenses was abandoned for failure to respond to an office action. As Bruce points out, abandonment of an application is not an abandonment of a trademark or a certification mark.
The question of descriptiveness is, well, tricky. Without passing on whether the mark OPEN SOURCE is merely descriptive rather than suggestive as used for licensing services, I will note that even if it is merely descriptive, the mark could still be enforceable if it had obtained secondary meaning. These subtleties are often overlooked in thinking about trademark cases, but they would be at the crux of any legal dispute if one arose.