Blackberries, OCD, and who does my attention belong to anyway ?

Trevor Cook points to an article about Blackberries affecting meeting behaviour.

Breakfast this morning with a manager who spent the   time groaning about the way people in meetings now sit around sending text   messages on their mobiles or checking and sending emails on their Blackberry.   Does technology make our attention spans shorter?  [The   Age]                                           

This is, for me anyway, similar to some of the discussions about backchannels at conferences, and opinions seem to vary mostly depending upon whether one is a speaker or a regular attendee: speakers often hate the fact that people aren't paying attention to them - attendees hate the fact that most of the the time they are bored and unengaged by the speaker.

So, at meetings, is the person blackberrying to fill up dead time really the problem , or is it the speaker who is talking only to hear themselves talk ?