Until now, the DRM-scheme provided by Adobe's Content Server lets users activate their ebooks on a fixed number of devices. This way it was not possible to transfer an ebook to someone else, unless their devices would be authorised first.
According to
this article in Computerworld, Adobe intends to add a new DRM scheme in Content Server 5, allowing publishers to select an alternative 'lighter' DRM method, using username and password protection. This way a user can share his ebooks with trusted friends, like relatives or close collegues.
The downside: when a username/password combination is illegally spread together with the ebook, there is no 'protection' anymore.
With the new DRM scheme, Adobe wants to cater to publishers with different protection needs.
Of course, in my opinion, the best DRM is no DRM at all (or social DRM), but it is not up to Adobe to decide this - this is the publishers' choice.
(via
@wdejager)