"Daily Active Users (DAUs). We define a daily active user as a registered Facebook user who logged in and visited Facebook through our website or a mobile device, or took an action to share content or activity with his or her Facebook friends or connections via a third-party website or app that is integrated with Facebook, on a given day. We view DAUs, and DAUs as a percentage of MAUs, as measures of user engagement."
instagram and other sites that use Facebook login count for DAU.
So is Facebook becoming more addictive or just more integrated.