Dear list members,
I'm sharing this with the list since so many members also use Academia.edu.
A while back I had an email exchange with a list member and the same day I received an email from Academia.edu highlighting a paper by the list member I'd just been emailing. Today I received an email from a colleague not a member of Academia.edu. That email discussed a particular hymn and had the hymns name in the email title. Within 15 minutes of receiving that email, I received an email from Academia.edu highlighting an article about the hymn I'd just been emailed about.
I use Gmail. I think this means that if you are a Academia.edu member and also a gmail user, then Academia.edu knows who and when you email someone or someone emails you, the title of the email and possibly the contents of the email.
As far as I can see looking at the Gmail privacy, Gmail doesn't say they don't share email contents and I think to join Academia.edu you have to give them access to your contents list.
I've removed Academia.edu from access to my contacts list and hopefully this will solve the problem.