The thesis elaborates on a topic which has attracted a lot of discussion in recent years and is the subject of an ongoing debate. A big controversy has flourished between the company Google Inc. and several privacy groups' ostensibly led by the "Working Party on the Protection of Individuals with regard to the Processing of Personal Data". Deep data protection concerns have been raised in this debate by the use of a search engine and its storing of personal data belonging to the data subject. There exists a legal conflict on how to qualify the status of an IP-address in light of it being considered as personal data under European legislation. The debate is continued in evaluating the status of a search engine provider in terms of classifying it as a controller under European legislation. In this context a deep examination is carried out with Art. 2 (a) and its recital 26 of Directive 95/46/EC in interpreting the term "all the means likely reasonable" in the identification process and what the term wants and should encompass. A deep examination is carried out if a lawful approach of the stakeholder involved is necessary when acquiring additional data on the data subject. Main focus is rested on a legal qualification of an IP-address.