The Green/Gold distinction (which is based on who provides the access: the publisher [Gold] or the author [Green]) is more important now than ever, as publishers fight to retain control of their content. The distinction resolves confusion and is simple to understand (but then needs to be adhered to).
The OA movement should resolutely push for Green OA; Green OA mandates should be formulated to ensure that
compliance is by the party bound by the mandate (the fundee, if a funder mandate, the employee, if an institutional mandate). On no account should mandates rely on compliance by a 2nd party, the publisher, who is not bound by the mandate and has every interest in maintaining control over the content.
There is a 3rd way in which articles can be made OA of course, other than by the author (or the author's assigns) (Green) or by the publisher (Gold): It can be made OA by a 3rd party -- either a user or a rival publisher or service provider. This is partly what the
Elsevier/academia.edu kerfuffle is about, and it will no doubt spread to other 3rd party providers like ResearchGate, Mendeley and the like. (It also concerns versions, because Green OA usually involves only the author's final draft whereas 3rd-party OA often involves the publisher's proprietary version-of-record.)
My advice to those who are up in arms about Elsevier's take-down notice for 3rd-party service providers is to redirect your resentment toward doing something legal and feasible, namely, mandating and depositing the refereed, accepted author-draft in your institutional repository immediately upon acceptance, and making it OA as soon as your can (or wish).
The term "OA" (and the goal of the OA movement) should also continue to be reserved for immediate (online) access. The inverse of Open Access is Access Denial. Access is denied by Access Tolls (subscriptions, licenses, pay-to-view); but, just as surely, access is denied by Access Embargoes. Hence it is a contradiction in terms to call Embargoed Access "Delayed Open Access." It is Delayed Access (DA), just as Toll Access is Toll Access (TA), not "Toll Open Access!".
And
a one year access embargo is now the real target to beat (as publishers already know all too well). Access delayed for a year is not a victory for the advocates of Open Access; nor is it a solution to the Access/Impact problem in the online era. A 1-year delay might be a
convenient unit for doing bibliometric measurements on the growth and latency of Green and Gold Access (and a welcome compromise and marketing ploy for the publishing industry), but "Open Access" should continue to be reserved for
immediate, toll-free (and permanent!) online access.
Stevan Harnad