Tim O'Reilly had a wonderful post on the alternatives for Internet development from the 'small pieces loosely joined model' to the "One Ring to Rule them All".
Led by Apple and now Google's Android, we may be emerging from the 'One ring to rule them all' model of the PC-centric era. But that does not necessarily mean we stay in an open standard universe. It seems that for generation(s) computing has moved from one natural (or unnatural) monopoly to another. The Social Web may be no different as companies such as Facebook and GOOG can, in many ways, wall-off competition/innovation. This does not mean they will, but the potential is there and, if it produces a better (e.g. safer, more intuitive, more reliable) experience, history shows we will facilitate them doing it by choosing today's experience over tomorrow's potential.