I'm worried by how much time my teenagers spend staring at screens. But it's hard to know whether they're addicted or just coping with everyday life. After all, every single adult I know walks around with a mobile on red alert. You can't even have a conversation without someone whipping out an iPhone to check the weather in Birmingham.
'When can you come round?' I asked the window cleaner, who was working two doors down.
He frowned. 'Text me,' he said. 'Or email me.'
But I worry that teenagers bear the brunt of information overload. They're surrounded by screens all the time - PCs, laptops, tellies, mobiles. In my day, a whirlwind of activity was reading a book while listening to the radio. Now they're simultaneously texting, gaming, poking, posting, downloading music, talking on their mobiles...and, apparently, doing their homework.'She's up in her room for hours,' says a friend whose daughter is 15. 'It gets to ten o'clock, and I say, time to stop now, and she says, but I haven't finished! And I think, have you really been doing maths and English all this time, or have you been chatting on Facebook?'
Of course you can do your best to monitor all this frantic activity. You can limit all the lovely toys. (I think we're probably the only family in south London with only one telly.)
You can say, quite honestly, that no one knows the long-term effects of buzzing from task to task like a fly in a sweetshop. Some very clever people have argued that teenagers, whose brains in these formative years are being pruned into adult shape, will end up with the attention span of kittens.
But I do wonder, in my darker moments, that maybe that's what the future will demand of them. Maybe one day everyone will have to be a technological multi-tasker. Every office will be like the Starship Enterprise with just one very busy Captain Kirk skidding from console to console.
What a horrible thought. As Mr Spock said, it's life, but not as we know it.