. We define a monthly active user as a registered Facebook user who logged in and visited Facebook through our website or a mobile device, or used our Messenger application (and is also a registered Facebook user), in the last 30 days as of the date of measurement. MAUs are a measure of the size of our global active user community on Facebook.
"The numbers for DAUs and MAUs do not include Instagram, WhatsApp, or Oculus users unless they would otherwise qualify as such users, respectively, based on their other activities on Facebook."
Their old 10Q said this:
> An active user is someone who visited Facebook.com and logged-in (or has been logged in) or who has taken an action with a Facebook feature (for example, clicked a ‘like button.)
The current ones say this:
> a monthly active user as a registered Facebook user who logged in and visited Facebook through our website or a mobile device, or used our Messenger application (and is also a registered Facebook user), in the last 30 days as of the date of measurement.
Clicking a like button is no longer sufficient to count as an active user. I believe there were articles about this when they changed it, but I'm not sure.
Maybe anything using facebook login counts as an activity. I.e. people that login to spotify with FB, but never use FB.