Some of you may have noticed the new Share button in SharePoint 2013. Without going into great detail, the Sharing metaphor is plugged in throughout SharePoint as a means for anyone to request and grant access, for themselves or someone else. If you are logged into a site where you are not a site collection administrator though, you may notice that the Share button is not visible. What you need to know is that the Share option doesn't appear for non-administrators unless you configure two things in Central Admin...System Settings...Configure outgoing e-mail settings:
Sharing brings some pretty nice features into SharePoint 2013 so it's worth spending a little time on it to get to know it better.