Technologies for classifying mathematical digital educational materials are often based on the adoption of metadata formats facilitating machine processing and management of information. A specific standard, called Learning Object Metadata (LOM), was developed to describe e-content in education and to accommodate the requirements of archiving, searching and retrieving learning materials. Metadata itself does not specify how to classify content and many taxonomies and vocabularies have evolved over the years. This poses the question of choosing a classification scheme for guiding browsing of the archival material. We compare existing taxonomies with respect to usage in mathematics education, motivate the choice of the LivingTaxonomy, aka MathTax, and discuss issues arising on modifying and enlarging the taxonomy.

Among the activities that involve the usage of the Living Taxonomy, we describe the repository for digital learning materials developed in the Joining Educational Mathematics (JEM) thematic network and ongoing work for a browser and repository of our collection of interactive MapleTA question banks. In the JEM repository, the LOM records for the registered content coexist with keywords entered freely by users. Taxonomies created by users are a novel web 2.0 approach that describes the knowledge space of a community in its evolution.

Some e-learning environments, like MapleTA, do not support the automatic creation of metadata for classifying contents. While this limitation might not be felt when the variety of content is small, it soon hinders search and administration as the variety grows. Authors have to give informative names and structure the material well in order to be able to find items that have been created. Importing MapleTA question banks to our MapleTA repository, allows browsing and searching not only according to metadata, but also in the questions texts and in keywords.