People have become more intentional about the ways in which they share information online. While you might use online social tools like Facebook to share pictures taken at a church gathering or engage in discussions of ongoing medical treatment, you may not want these items broadcast to the general public. So people take steps to ensure that the information that they would like to keep private is not publically available.
But now some employers are seeking access to this personal and private online information by demanding that prospective employees provide passwords to Facebook and other social networking services. Employees obviously feel pressure to comply with this request in order to get the job, despite the invasion of privacy it represents and the potential that the employer might take some illegal job action based on protected characteristics they discover in your online networks.