There's a bunfight going on right now over what Open Access actually is.

First there was the Berlin declaration:

Open access contributions must satisfy two conditions:

1. The author(s) and right holder(s) of such contributions grant(s) to all users a free, irrevocable, worldwide, right of access to, and a license to copy, use, distribute, transmit and display the work publicly and to make and distribute derivative works, in any digital medium for any responsible purpose, subject to proper attribution of authorship (community standards, will continue to provide the mechanism for enforcement of proper attribution and responsible use of the published work, as they do now), as well as the right to make small numbers of printed copies for their personal use.

2. A complete version of the work and all supplemental materials, including a copy of the permission as stated above, in an appropriate standard electronic format is deposited (and thus published) in at least one online repository using suitable technical standards (such as the Open Archive definitions) that is supported and maintained by an academic institution, scholarly society, government agency, or other well-established organization that seeks to enable open access, unrestricted distribution, inter operability, and long-term archiving.

Which is pretty unambiguous, you'd have thought.

But Open Access, informally, has been since used to mean "you can read journal articles without paying". People've, unsurprisingly, been confused; resulting in an effort to clarify matters by coining, and within a few days repudiating, of the terms "Strong OA" and "Weak OA" by two prominent Open Access advocates, Stevan Harnad and Peter Suber.

Weak OA means you can read the paper for free online, but not (necessarily) do anything with the content; Strong OA itself is subject to argument, but allows reuse of, and the making of derivative works from, the content of articles beyond fair use. (The argument's over whether requiring that use to be non-commercial stops it being Strong OA - the people coming from the free software community arguing that it should, by analogy with the Open Source Definition).

The upshot is that, in the OA world, no-one knows what anything means right now.