Mendeley, Academa.edu and ResearchGate all began as solutions created by scholars but they have all subsequently ‘sold out’ to some degree.
RG has secured $35M from major investors including Bill Gates. Academia has raised c.$18M from venture capital. Mendeley sold to Elsevier $76M (Van Noorden 2014)
They are now looking for a return on their investment and have adopted aggressive strategies to increase the networks. They are also looking to use them to build databases of shared files, develop analytical products to sell back to universities and sell advertising space (including to employers). this trade-off of personal data for the product is no different from much internet activity but Scholars should be aware of it.
The massive advantage of Humanities Commons is that it does not have these other motivations and remains in the hands of Scholars.