As with most content, the creator should consider the audience - what they want, why they want it, and why they should get it from you. In the case of speaking, this is more relevant than ever. After all, who wants to be in front of a group of people who don't care about what you're saying? Not me!
Nick Morgan has posted a 9 part series on how to write a great speech. His rule #1? Consider the audience. In fact, audience is considered in each of his 9 tips, making it clear that it's not just the content that is important, but the context of that content, and how to effectively make the bridge between an idea, and people that will absorb and use it. Check out the whole series and polish up your presentations.