It seems to me that a slight modification of Vygotsky's definition of ZPD reconciles the Piagetian and Vygotskyian views. For me, the ZPD is the zone in which learning is made easier through support by differently abled others. These others may be physically present, or remote in terms of location or time. Vygotsky and Piaget both provide support for my learning through the extension of their knowledge in written media. Steve Wheeler, amongst others, provides geographically remote support through blog posts (and more on that one later) and my colleagues at OdinLab at the University of Reading (e.g. Shirley Williams) provide support through direct contact as well as through the more remote methods.
Via Dr. Susan Bainbridge