Why is my account following people while I was logged out?
When you connect your Academia.edu account to your Facebook or Google+ profile, you automatically follow your friends from those networks who are also on Academia.edu.
When your Facebook/Google+ friends create new accounts on Academia.edu, you will automatically follow them as well. This explains why you are suddenly following academics that you do not recall choosing to follow. This also accounts for following activity on your profile while you were logged out.
What else happens when I connect my account with Facebook or Google+?
This article will give you an overview of these social connect features.