Seeing No Progress?
Just read the NY Times article about phasing out personal laptops in the classroom. It raises some good points about attention span, the focus on surfing instead of learning, and how some things are best experienced with pen and paper. The school that's phasing out the laptop program cited the lack of academic progress of its students and rising costs of maintenance as additional reasons for stopping.
The article struck a chord with me because I have the same questions about their effectiveness in conferences as well as classrooms. I know that I work during conferences if there's a laptop in front of me, and that many of my colleagues IM and surf. Other colleagues have told me that it distracts from their involvement if they see a sea of people typing away instead of paying attention to presentations. As a presenter at conferences, it can be downright disconcerting to face a room of apparently disinterested people (though it does help with stagefright!).
As I help plan conference and classes, I wonder if it's best to put a stop to the technology intrusion. Laptops have their place, but should they be present in a learning environment? From my own experience, I think we're better off without them.

I agree that laptops can be abused in classroom and conference environments. I spent a quarter TAing for a bunch of undergrads, and I was aghast at the percentage of students that were shopping for music on iTunes or who had multiple IM windows open.
But, for my use, I like using a laptop for taking notes for several reasons. First, my handwriting is atrocious. Second, I can instantly cross-reference my notes with instructor presentations. And, third, my typing speed far exceeds my writing speed - I can also go forward and back much easier within my notes as ideas come to me.
But, with all things, there is a time and place. There are environments I wouldn't dream of bringing a laptop in my professional life.
The CSCW 2006 conference in Chicago had a session on technology in classrooms and a discussion around backchannel (in classes and conferences). Liz Lawley and other speakers talked about integrating technology into the classroom experience, rather than simply having people bring their laptops. Without knowing what these schools are doing, it sounds like they gave the students a new tool and didn't give the instructors any warning about how that tool might impact their classroom experience.
I recently used my laptop to take minutes at a four hour meeting and discovered that it did help be better capture the ideas from the meeting, it also significantly curtailed my participation in the meeting and learning from the material presented. As a woman I know I need to make eye contact with the leader and other participants to feel connected to the material being discussed and definitely lost this ability when staring at my laptop screen.