Importance of audience analysis and adaptation?

If you want to deliver a speech that everyone will want to listen to, then the speech needs to be interesting and about something that is somewhat familiar to people as a whole.  When I listen to someone give a speech, the first thing I want to know is the topic.  If the topic is something that I am interested in, I am more likely to stay focused.  By adapting to the audience and what they like, you are more likely to have a positive feedback.  I find medical-based speeches are my favorite because I work in the medical field and am always wanting to expand my knowledge on the subject.  I also believe that if a person grasps the audience in a unique way, a boring topic can go to an exciting topic.  It's all in the approach and how well you present the information at hand.  Being familiar with the audience is extremely important, but delivering a fantastic speech take it to a whole new level.