Alerts should signify events that you can do something about. It is important to remember to alert only on actionable items. This is especially meaningful when administrators are paged outside of work hours. Certain performance metrics are very important in order to understand and improve your system, but they are not immediately actionable.
Some alerts are informational and need to be acted upon in the short term (for instance, "the file storage will be full in a month") or even in the long term (for instance, "70% of users leave the site before purchasing"). These alerts should be labeled appropriately and raised via non-invasive channels, such as email.
Other alerts are critical, but cannot be fixed by the ...
