This is an edict from their excutive branch of government. Mr. Eric Kriss has been working on it up there for years, here's an article from 2003:
http://www.boston.com/business/technology/articles/2003/12/22/open_source_battle_is_heating_up/
The future of the computer software industry was being fought out last week in the Massachusetts Senate. Our state's role in the drama began in September, when a remarkable memo leaked from the office of Eric Kriss, Massachusetts secretary of finance and administration. The memo said, or seemed to say, that the entire state would abandon the use of traditional computer software and replace them with "open-source" programs.
Still waiting for a Bill number....
A memo isn't the same thing as implemented policy, and it would seem that in the two years since, it hasn't become policy. Also, requiring all software used by the state to be Open Source isn't the same thing as standardizing on a single document format.