IP Addresses - Just a Number?

Should IP addresses be regulated as personal data under the European Union's Data Protection Directive? Where do we draw the line separating personal from anonymous data, and which means of identification should be taken into account when we make decisions about whether or not IP addresses can be related to an identifiable natural person? These are the questions raised and discussed in this article. After first having examined the arguments presented by European courts for classifying IP addresses either as personal or anonymous data, we then propose a method for determining the legal status of IP addresses. This method consist of two separate but interrelated steps: the legality test and the likely resonable test. It is our contention is that this method is not only applicable to IP addresses, but should be regarded as a general way of evaluating the relationship between natural persons, identifiability and information.