Normally the sort of thing I'd avoid as Luddite scaremongering, but this is Susan Greenfield talking and she does tend to know what she's talking about...
"She said she found it strange we are 'enthusiastically embracing' the possible erosion of our identity through social networking sites, since those that use such sites can lose a sense of where they themselves 'finish and the outside world begins'.
She claimed that sense of identity can be eroded by 'fast-paced, instant screen reactions, perhaps the next generation will define themselves by the responses of others'."
Facebook et al risk 'infantilising' the human mind | Media | guardian.co.uk
How are you coping with collapse-anxiety? - Boing Boing: "I lived through the dotcom boom and bust in San Francisco, arriving in 1999 and departing in 2003, and the two things that stand out for me were 1) how fast it fell and how deep the bottom turned out to be and 2) how quickly the unthinkable became normal and people started to have fun and do cool stuff even without the stupid amounts of money sloshing around the city,"