If you've shared a dashboard with any lists or individuals directly you can see who has viewed a dashboard, the last time and how many times cumulatively.
Simply navigated to your respective shared dashboard and click the "Share" button in the top right of the dashboard.
The Share modal will open and you can see the dashboard view stats and manage your permissions.
As always, send any and all feedback our way. If you are looking how to share a dashboard you can find it in this article: http://support.visible.vc/dashboards/how-do-i-share-a-dashboard