Wireless networking has changed the modern conference in many ways. If you're noticing people are spending more time looking at their laptops and paying less attention to your presentation, you might consider these helpful tips from Confessions of a Public Speaker.
Every audience has a culture, and in some cultures it's common for people to stare at something other than the speaker. This often takes energy away from the speaker, so it's usually to the speaker's advantage to have as much eye contact from the audience as possible. Sometimes people are just taking notes or sharing what you say with other people, which is good for you, but other times they're playing Solitaire or wandering the Web, which isn't good. People in the audience should be free to choose how they want to listen, but you are also free to influence how they make that choice.
How to prevent:
You can ask people to close their laptops. Don't demand it—respect their right to do what they like, especially if they are paying to be in the room. But you can tell them you think you'll do a better job if you have the room's undivided attention.
Sometimes I say the following: "Here's a deal. I'd like you to give me your undivided attention for five minutes. If after five minutes you're bored, you think I'm an idiot, or you'd rather browse the Web than listen, you're free to do so. In fact, I won't mind if you get up and leave after five minutes. But for the first 300 seconds, please give me your undivided attention." Most people close their laptops.
Keep in mind that some people take notes on their laptops. They might be live blogging or tweeting what you're saying, vastly increasing your audience beyond the room. An open laptop doesn't always mean you're being ignored.
How to respond:
There isn't much you can do, but you should focus on the people who are fully engaged.
Go with the flow. Have Twitter open on your laptop, project it on the screen, and take a moment midway through your talk to review comments and questions.
Ask the host to monitor Twitter or the event chat room as a way to get the best questions and comments from the back channel into your presentation. Let the audience know this is happening and how they can send a question to the host.
Learn more about this topic from Confessions of a Public Speaker.
In this hilarious and highly practical book, author and professional speaker Scott Berkun reveals the techniques behind what great communicators do, and shows how anyone can learn to use them well. For anyone else who talks and expects someone to listen, Confessions of a Public Speaker provides an insider's perspective on how to effectively present ideas to anyone. You'll get new insights into the art of persuasion, based on Scott's 15 years of experience speaking to crowds of all sizes.