Especially in the latter stages of the sales process, we are sharing Sales Documents with leads quite extensively. Whereas the tracking and reporting on the Sales Document page itself is good - I can see a full list of who downloaded the document - the tracking and reporting on the contact page is very limited.
I propose to enable clicks on a 'Sales Document' to be used as a trigger (e.g. for a workflow) in the same way you can do this with Page Views. This can then be used in a range of funnel activities, e.g.: