McLuhan divides history in 4 discrete seasons: oral tribe culture, manuscript culture, Gutenberg galaxy and electronic era. Every stage is distinguished by a new invention with enormous social impact: literacy, typography and information society. Online social networking is a technology (in a wider consideration) that may be leads to the next stage, to hybrid society era. I think hybrid society is a distinct era because social relations change dramatically by the addition of a virtual part, a virtual lived experience that is complementary and multiplexed with normal lived experience.
People today interact socially in a natural world and the same time interact socially in a computer mediated world, in the world of online social networking. Both social interactions are lived by the very same corporal human body. So they are not distinct experiences but they rather consist a unique hybrid social lived experience.
I think Hybrid Social era as a distinct nest stage of information society because of two major reasons. Hybrid social networking experience is completely new social experience with the theoritical possibility to be connected with all the world population through the friends-of-friends capability, never known before. Second by the characteristic of the powerful social construction of identity. In facebook we are known by our friends and what they say about us.