Over the past years, several Open Educational Resources (OERs) initiatives have been emerged worldwide aiming to create, share and reuse digital educational resources among educational communities. As a result, organizing, offering and accessing these resources over the web have been key issues for both the research and the educational community. Traditionally, a popular way for characterizing digital educational resources is by using a formal and centrally agreed classification system, such as the IEEE Learning Object Metadata (LOM). On the other hand, with the emerging Web 2.0 applications, the issue of characterizing digital educational resources tends to move from the expert-based description based on formal classification systems to a less formal user-based tagging referred to as social tagging. As a result, a number of studies have been reported in the field of Technology-enhanced Learning (TeL) aiming to evaluate whether social tagging can improve the discovery of new digital educational resources and the retrieval of known ones stored in web-based repositories. Additionally, recent studies in the field of social tagging systems has provided initial evidence that users' tagging motivation has a direct influence on the properties of the resulted tags and folksonomies. Thus, in this paper we aim to propose a methodology for investigating this issue and examine whether different end-users' tagging motivations (that is teachers) could enlarge the metadata descriptions of digital educational resources. The results of our study provided us evidence that there is a direct influence of users' tagging motivation on the enlargement of metadata descriptions of digital educational resources, as well as to the resulted folksonomy when it is compared with formal structured vocabularies used by metadata experts or content providers for characterizing digital educational resources. (Contains 6 tables.) [For the complete proceedings, "Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on Cognition and Exploratory Learning in Digital Age (CELDA) (Madrid, Spain, Oct 19-21, 2012)," see ED542606.]