As presenters, it is very tempting to pontificate from center stage as the subject matter expert, inflicting slide after slide after slide on a passive audience. However, both you and your audience will be rewarded when you view your presentation as a two-way street...communication flowing both ways.
According to Michael Moon, Creative Director of Duarte (the firm that helped create Al Gore's Academy Award-winning documentary An Inconvenient Truth), it's not about the slides, it's about the experience. [Listen to his tips on this podcast]
Making the audience an active participant in the presentation is one way of enhancing the experience.
QUESTIONS CREATE GIVE AND TAKE
Although every presentation may not lend itself to extensive dialogue with, or input from, the audience, you always have the option of asking your audience questions to engage them. In a large group, go for rhetorical questions or polling questions (ones asking the audience to vote by show of hands). In a smaller group, ask "real" questions where you actually wait for an answer.
Every time you use a questioning technique, your presentation becomes more of a give and take. Even an answer that is articulated only in the listener's head increases the level of involvement.
Create more of a two-way street with your audience...let them participate...and you'll both get more out of the experience.