good question to ask when you are ready to put your presentation together is "What do I want my audience to do with this information?" If you want them to walk away with new information that makes them smarter people, you were speaking to inform. If you want them to laugh and have a great time, you were out to amuse. If you want them to go out and use your web site, to join your political party or stop hurting the ozone layer, the objective of your speech is to convince.