I have been using PRTG for a long time now. Now that our installation has grown to be supported by many Administrators, we have found the need for Incident Markers with comment references.
The good place to see the Incident Makers is/are in the Graph(s) for the specific device, at a specific time or across a time frame. All configured Device sensor graphs would then contain the same Incident Marker(s).
These Incident Markers need to be indexable, for the ease of Incident tracking.