You can track content usage through the Content Insight Dashboard, but you can also stay informed in realtime with Chatter. KnowledgeTree content usage updates are surfaced in Chatter in real time.
All you'll need to do is simply follow the record. In the Opportunity or Lead view that you wish to get real time content usages updates on, click to follow.
This will allow you to see all KnowledgeTree activity in real time right within your Chatter Feed.
This is a great way to track hot prospects. You can know who is engaged real time so that you can follow up and close the sale.