When you clicked the vertical arrow on the top-left corner and then clicked People, you will see a list of people in your contacts list.
Then when you clicked on any one of the contacts in the list from the left, you should see the person's profile picture and his/her contact on the right.
However, out of the many contacts I have, there's only one contact in which I can only see his name and profile picture, but the column for Social/Email/etc. is missing entirely.

What does this mean?