One could have long arguments over the exact definition of socialism if it?s posed as an abstract future-construction. However such a discussion will acquire different quality if we are to base it upon real processes which we can observe in the present reality which are already undermining and (or even outplacing in certain conditions) the established models.
Why not start with Wikipedia and other examples of so-called peer production that are challenging traditional hierarchical capitalist business models? Wikipedia is a profoundly anti-capitalist and even communist way of producing and distributing knowledge. It is based on the principle to each according to need, from each according to ability. The contributors or editors are not paid and the users are not charged, which again flies in the face of all capitalist logic. Furthermore, Wikipedia is egalitarian produced on the basis of horizontal reciprocities rather than hierarchical control.