I think there are too many different opinions on how to implement this that makes it impossible for me to vote. 

I agree with privacy settings but some of the recommendations here are extremist. 

I agree with a block function (I think this is standard on all forums)

However, I cannot agree with privatizing a profile picture or the standard list.  Part of MDL is about sharing and that is my minimum. If I dislike someone's tastes then I want to be able to consider their list as much as consider someone's list that I feel have similar tastes... 

The only thing I think is really important is the privacy about PM. Right now even blocked users can write you a PM.