I think "works" can include digital artifacts — to my understanding, this was part of the Mozilla Foundation's rationale for exemption. But Mozilla's "public work" was the Internet as a free platform, not just some piece of software used by some unidentified group of people. Mozilla compared the Internet to a public road, and depicted its role in maintaining the Web as a free and open platform as being similar to ensuring that roads are well-kept and accessible to everyone.

Yorba's application appears to have been more along the lines of, "We make free software. Poor people can use free software and other programmers can learn from it." (I'm basing this on the IRS's response — I can't find a full copy of Yorba's application anywhere.) So I can kind of see why that appears less compelling from a "public works" perspective to the IRS.

The IRS contends otherwise; from http://yorba.org/docs/IRS-determination-letter-final.pdf, page 8:

> Software is not a public work. The development and distribution of software is not a public work even if published under open source or creative commons compatible licenses because software is not a facility ordinarily charitable to include "erecting or maintaining public buildings, monuments, or works." This language slightly broadens the original formulation from four centuries ago.

It goes on to quote the Charitable Uses Act of 1601.

Sure, if "maintaining a work" counted, the standard would be pretty easy to meet!

But it's not just "works" but "public works." As in, "a broad category of infrastructure projects, financed and constructed by the government, for recreational, employment, and health and safety uses in the greater community." http://en.wikipedia.org/wiki/Public_works (Yes, it's Wikipedia, but this definition is about right.)