DARIAH’s Erzsébet Tóth-Czifra, urging scholars to shun the VC-backed for-profit sites Academia.edu and ResearchGate:

What we need to realize is that ‘the “everybody” factor’ (as Kathleen Fitzpatrick calls it) that makes ResearchGate and Academia.edu success stories is in fact our own presence. Going against such community practices both one by one and collectively to give rise to and flourish other, more sustainable author-sharing mechanisms is extremely challenging and takes a great deal of courage. But only this will enable us to move away from platforms that do not do any good for fair sharing of our scholarship and replace them to publicly maintained environments/the population of the development of collectively maintained public services, where scholarly communities have a say in which roads should be paved.

There’s an excellent chart and list of alternatives.