Social and professional networking sites are all the rage. They offer more practical benefits than searching for old school mates (the result of which has left many marriages in post-affair tatters) as they can get you in front of a vast network of colleagues and customers. The problem is they also act as a great source of private information useful to hackers and ID thieves.
According to this article on the Register SecureTest were able to build up a profile of an employee by harvesting data from sites such as LinkedIn, Ryze and Ecademy. Many people list personal data including a full employment history, qualifications and hobbies. From this a whole bunch of stuff can be extrapolated and guessed – I am sure this includes passwords and birth dates as well.
This really makes you think. Bottom line – be very careful what you stick up on public sites.