How do I edit the E-mail contact list?

Why does Quora "need" people's  (FB) friend list, education history, work history, likes, hometown, email contact list, plus the right to "manage" the contact list and more?

• Why does Quora ask for the following user information at the time of signup: (FB) friend list, custom friend list, education history, work history, likes, hometown AND (Gmail) access contact list, manage contact list, identify on Google+. How they use these information? Why they "need" it? When I signed up with Facebook, I was asked for these permissions then I was asked to verify my email (gmail) id followed by more permissions to access my gmail account information which I mentioned in the question. Isn't it way more information then they actually need? If I have already given access to information on my Facebook account, what is the need to access information on my google account?

• Answer:

  Probably to customize your feed based on your interests and suggest you people to follow.