It seems that in the tech world, presenting a live twitter feed behind the presenter is becoming more common.

The way it works - the presenter presents, the audience listen and what the audience thinks as they listen, they Tweet - then the tweets are presented as a live update on the screen behind the presenter (so if someone tweets something funny, then the audience laugh regardless of how serious a point the presenter is making).

You can read an interesting article by Keir Whittaker which draws together some experiences of this in practice.

From our point of view at corporate events for UK companies, using Twitter 'live' could be a fantastic way draw in questions or comments for a Q&A or to promote interaction during a dedicated session for interaction, but the idea of having the audience accessing their phones and contemplating what to tweet during a presentation will inevitably lead to them not hearing or engaging with the very message that they are attending the conference to hear - which can only be a bad thing.

This is a video monologue from CNNs tech expert Chris Pirillo following an apparently bad experience at the Web09 conference in Paris: