Adding to Kathleen Fitzpatrick’s critique, I also recommend the following paper by Gary Hall:
Should this be the last thing that you read on Academia.edu (on Academia.edu) that is also available as What does Academia_edu’s success mean for Open Access? The data-driven world of search engines and social networking (on the LSE blog website):
Academia.edu has a parasitical relationship to the public education system, in that these academics are labouring for it for free to help build its privately-owned for-profit platform by providing the aggregated input, data and attention value. We can thus see that posting on Academia.edu is not ethically and politically equivalent to making research available using an institutional open access repository at all.