You can use a tool like the TWB auditor:
There are a few others out there--Interworks now has a data source auditor, and I think I've seen a few others referenced as well.
Is there a mechanism (any mechanism) to determine if a view or table I reference is used in any dashboards (or extracts)?
O, how I wish this was easy to do for Tableau Server workbooks!
As for the mechanism, I just collected various tips in The specified item was not found..