Recently I was asked how to receive notifications when specific metadata for an item changed. I recalled this was somehow possible with the out of the box Alerts and then configure them to send a notification when something to the View changed.
“This feature is not available when I create an alert for my [List|Library] ?”
This feature is only visible when there is a filtered view defined for your list or library. Once that condition is met you can create Alerts on Views.
Simple stupid :)