  Big Data dealing with the social produce predictive correlations for the
benefit of brands and web platforms. Beyond "society" and "opinion" for which
the text lays out a genealogy, appear the "traces" that must be theorized as
"replications" by the social sciences in order to reap the benefits of the
uncertain status of entities' widespread traceability. High frequency
replications as a collective phenomenon did exist before the digital networks
emergence but now they leave traces that can be computed. The third generation
of Social Sciences currently emerging must assume the specific nature of the
world of data created by digital networks, without reducing them to the
categories of the sciences of "society" or "opinion". Examples from recent
works on Twitter and other digital corpora show how the search for structural
effects or market-style trade-offs are prevalent even though insights about
propagation, virality and memetics could help build a new theoretical
framework.
