# Digital Libraries: The Challenge of Integrating Instagram with a Taxonomy for Content Management
## 10 Comparing the Metadata and Resulting Metadata Taxonomy  
We compared metadata from the standards analyzed during the first phase to the data collected during the second phase. The combined approach results from the combination of the previous phases, starting by defining the key concepts and then generalizing and specializing them appropriately. The purpose of the comparison is to verify whether all the features studied during the second phase are represented by the metadata obtained from the first phase. If they are not, new metadata are created, either as an extension of the already chosen metadata (DC allows semantics extensions by adding qualifiers) or as entirely new metadata, creating a new namespace to include them. The process began with a mapping phase, followed by the creation of new metadata and other considerations, such as the representation of ebooks and rights management. Once the iterative phase was completed, and all available metadata were selected, the schema of the taxonomy could be created. Firstly, it was necessary to perform a comparison between the list of tags and the previously selected metadata, considering their semantics. By doing this, tags whose semantics could not be described by already chosen metadata were identified, so that new metadata could be created for them. To tags whose semantics were similar to a DC element, but more precise, new qualifiers were associated, whereas tags that could not be effectively identified by the DC standard were included in a new namespace called \"multimediatype\". For instance, the following new qualifiers were created for the DC element \"dc:identifier\": \"isbn\", \"LoC\", \"dewey\", \"iccd\". Each one of these qualifiers represent a specific code associated with the digital resource. It is not required to create one metadata for each code type, but it was considered more appropriate to create four qualifiers of \"dc:identifier\" for the most important codes: International Standard Book Number (ISBN), Library of Congress Collections (LoC), Dewey, ICCD. For the other codes, the general \"dc:identifier\" can be used. The code type must also be specified when adding the new metadata. The namespace \"multimediatype\", instead, includes metadata describing legal documents, publishing information, institutions (for example, museums and libraries), and UGC. The results of our research showed that there were not any metadata suggesting the optimal software or hardware device for the exploitation of a resource, e.g., an ebook. To overcome this, two new DC qualifiers were created: \"dc.format.testedSoftware\" and \"dc.format.testedDevice\". These metadata define the most suitable software and device through which the resource can be exploited. Grey literature can be defined by the level of education of their target user (thus defining the suggested group of users that typically use a specific kind of resource), and the type of document, selected from a list of types that belong to that category (for example, papers, theses and scientific research documents). The metadata are: \"dc.audience.instructionLevel\" and \"multimediatype.documentCategory\". The integration of UGC metadata was performed by focusing on those that had a single semantic during the first phase, and selecting, among them, the most suitable for the DL context. Under the category \"multimediatype.ugc\", the metadata extracts from Instagram included \"user-id\" which are associated with \"follows\" and \"followed-by\", \"media-id\" which is associated with \"likes\", \"tag-name\", \"location-id\" in order to represent information about the user who provided the resource by Instagram.