I was recently called into create POC (Proof of Concept) for a project which was being planned for use StreamInsight. When I was there, I was also asked to give overview of the this feature to their CTO (who had only 15 minutes to spare). Usually I do not like sudden change of plans but the dynamic nature of consultation always gives me motivation to work more. I quickly talked few things in the session. In the evening, I had received the minutes of the meeting and had brief note regarding my discussion on StreamInsight. I am copy pasting the same brief note over here.
I hope this is useful to someone who is looking for high level overview of the StreamInsight.
Reference: Pinal Dave (http://blog.SQLAuthority.com)