Jeff Jarvis has written in Comment Is Free soon after the Guardian Activate event. It starts with the situation around whistle blowers but contains a useful definition of journalism-

journalism helps communities organize their knowledge so they can better organize themselves.

This is also covered in Buzzmachine, where he explains that there are no journalists as used to be understood. For the Guardian print journalists this may come as news. It may change the way that bloggers etc. are discussed.