From the first paragraph: "Today, Facebook is granting developers on Platform the ability to request <i>(or require)</i> users to hand over their email addresses so they they can send periodic messages directly to users." (Emphasis added)<p>So it's up to the developer whether it's optional or not.<p>Also see the Facebook wiki for more info:<p><a href="http://wiki.developers.facebook.com/index.php/Roadmap_Email" rel="nofollow">http://wiki.developers.facebook.com/index.php/Roadmap_Email</a>