With BSC Designer it is possible to create comments for KPIs that will be later added next to the diagram in HTML or PowerPoint report.
Comments can be added to the chart of KPIs.
1. Select any KPI on the "KPIs" tab
2. Click the "Initiatives" button
3. Add a new initiative
4. In the "Initiative" dialog click on "More...", select "Add chart tag," and select one of the charts
In this way you will associate a comment for this KPI with a chart diagram.
Try creating an "Scorecard Performance" or a "PowerPoint" report, and you will see that your text will be displayed under the Gauge diagram.