The term "commons" evokes for me an image of a dining hall, or perhaps an institutional living room, of the sort found in a "Student Union" building when I was an undergraduate. "Commons" says nothing about what goes on in the space, but asserts that it is somehow shared, or shareable: some sort of common property resource.

The OED's senses which seem applicable are

Provisions provided for a community or company in common; the common expense of such provisions; also the share to which each member of the company is entitled. Prob. originally in monastic use, afterwards esp. in colleges.
...or perhaps
(under 'common') A common land or estate; the undivided land belonging to the members of a local community as a whole. Hence, often, the patch of unenclosed or `waste' land which remains to represent that. Formerly often commons = L. communia.

In its application to information resources, the most relevant common property resource is in fact not confined to a specific space: it is, rather, the global and virtual 'space' of cyberspace and the Internet. This is the 'space' in which Garrett Hardin's "Tragedy of the Commons" may be an applicable metaphor, and the 'space' addressed by today's debates over Open Access (as chronicled in Peter Suber's Open Access News, in Lawrence Lessig's The Future of Ideas, and in a broad array of other analyses and commentaries I've linked sabbatical readings, and in mid-January entries to my notes on information commons conceptualizations and implementations)... and this is the space which we and our students will inhabit more and more. This is where scholarship is going, and where libraries must also go.