If the identity of the person who posted derogatory comments about it on a social networking site is unknown, what should the employer do?

If the employer does not know who the author of a defamatory statement posted on a social networking site is (for example, where an internet pseudonym is used), it is likely that the website will hold some information from which it is possible to identify the individual, for example an email address used to log into the account. The employer should write to the social networking site putting it on notice of the potential defamation claim and requesting this information. If the website refuses to provide the information (citing data protection reasons for example), depending on the severity of the statement, the employer could consider applying to the courts for an order, known as a "Norwich Pharmacal Order", requiring the internet service provider to disclose the relevant details (for example, the internet protocol (IP) address, which contains a unique number that can be used to identify separate visitors).