The Electronic Frontier Foundation (EFF) and the Open Society Initiative have created the very useful ‘Surveillance Self-Defense’ (SSD) site. Although the SSD is aimed at US citizens and the legal aspects are therefore more relevant to those living in the States, the general advice and information on risk management and defensive technologies is all worth reading for anyone who uses a computer anywhere in the world.
Essentially this is a kind of care and maintenance of your ‘data double’ concept, which is one response to the growth of surveillance. Of course no-one should think that this kind of ‘personal information economy’ approach is enough and the EFF certainly don’t. There is in any case a general effect that could emerge from this kind of action should large numbers of people start taking the advice of EFF: mass surveillance effectively becomes more difficult, more expensive and less worthwhile. However, things like SSD cannot be a substitute for political action to curb the powers of state and private sector to monitor us and reduce individual liberties and dignity.