I sent an email to someones Facebook using my Gmail address. It came back stating I was blocked by his privacy settings. Is this because I do not use Facebook, therefore, I am not his friend so it automatically blocks me?
Facebook's email service does have two privacy options, one being Basic Filtering and the other being Strict Filtering. Your friend may have the strict filtering on, which may be causing issues. Under the privacy tab, the options for this look like the below: