The ability to annotate a visualization, for example a chart or graph, would make both the dashboard and reports experience more robust.
'+1 - Ability for users to click any report visualisation, and add a free text annotation - Ability for annotation to display as either tooltips (absolute position) or overlay - Ability for users to toggle visibility of overlays/tooltips on/off - Write-back capability to capture metadata - e.g. user making comment, date/time of annotation, selected filters, selected report/page, etc.
