Personally I really don't want my email visible to Facebook. What would they do with my information? Google already set the precedent for leveraging email data _somehow_. If so, Facebook will probably push the boundaries while carefully marketing it so that users accept something they would not have just previously. I only have a problem with this because they're profiting from data that users would not have allowed them to sell to advertisers if they had known about the terms when signing up. So it's like a bait and switch and that makes me distrust them.