I like that phrase. Everyone I run it past gets it straight away. "Oh yeah, it's when you're watching TV and sending a text at the same time!" Yup. Or on your mobile when you're with a group of people, or using an interactive or website while you're chatting with a friend.
It's bubbled up to the surface again this week due to a couple of things. I was listening to an interview with the MD of Odeon cinemas. Strangely one of his biggest problems isn't bittorrents or DVDs - it's mobile phones. He stated that under 16s just don't get the fact that they shouldn't have full-volume conversations on their mobiles in a cinema, and typically 2 or 3 are going on at any one time during a film with this audience. Under 16's are cool with this. Older people are not.
Then I was at a do at Microsoft. They called it an un-conference, which has come to mean many things. This one meant that they live streamed a keynote address from the Mix09 conference in Vegas on a big screen, but at the same time you could play with demos, chat to friendly softies or get a beer. It was fun, but the level of information going in was compromised for me.
The really interesting thing is that I think I'm a dying breed. Clearly younger audiences have acclimated to absorbing information in this way to some extent. But the challenge facing user interface and user experience professionals will be how we manage to feed this growing audience in a way that both suits their "grazing" approach and provides quality information.