There's some good commentary in the comments section about some of the advantages and disadvantages to the speaker and audience of twittering. There's probably a distinction worth making between conference presentations and interactive discussions.
So I told them that class on the 20th would be an exception to HBS’s standard ’screens down’ policy (i.e. no use of digital devices during class), and that they could tweet using whatever device they preferred.
I’ll ask my students what they thought about the experience, but I thought it was miserable. Class discussion limped along at well below its normal levels of engagement, interest, and insight. I thought it was due to my bad class plan, a comparatively weak case, and/or the fact that the 20th was the last day before spring break.
Any or all of these could have been part of the explanation, but I’m quite sure that another part was the tweeting that went on. When I reviewed students’ tweets after class, I found that a lot of them remarked on how difficult it was to pay attention to what was going on in the room and on their screens. And it was very clear that the screens won.
Speaking to an audience that’s tweeting away is now a fact of life at most technology conferences (as clearly evidenced by this year’s South by Southwest). Laura says she likes it, and I’m eager to learn from her why this is and how I can turn live tweeting to my advantage when speaking. So far it feels to me like trying to talk to people who all have TVs in front of them. I realize that live tweeting might be beneficial to some constituencies (like the tweeters’ followers), but it feels to me like a pure negative for speakers. We’re now competing for attention with a very compelling interactive activity.
In the case of a typical presentation at a conference, I definitely get value out of the backchannel as a way to get the reaction of others in real-time. I find it often engages me more than merely being a passive observer.
And, if the speaker is really engaging with and connecting to me directly, I can just ignore the chatter. Of course, if the presentation is simply uninteresting, I can go off on the Web and do other things or simply snark on twitter.
On the other hand, in a participatory interactive discussion, I think it can indeed be a distraction--although to the degree I'm just using it to essentially record interesting snippets, it's really no different than taking notes. But, in general, if some number of a group is twittering or doing whatever on their laptops, it's pretty commonsensical that they're going to be distracted.
(I didn't know about HBS' 'screens down' policy though. Man, I can barely take usable notes by hand any longer.)