Rich and engaging interactivity is one of the reasons that events delivered via web conference are so compelling. At an online presentation for the Technology Special Interest Group of the Metro DC ASTD Chapter someone asked an interesting question: can you have too much interactivity in a web conference?
Although I tend to see the opposite problem -- too little interactivity -- I believe the answer to this question is yes. If the interaction does not support your learning objectives and you are interacting with participants merely for the sake of interacting, then it can frustrate your audience. Also, if you are using the interactive features of your web conferencing tool with your audience simply because you think the feature is neat and not to support your content, then the audience may feel like they are jumping through hoops pointlessly.