Abstract
The integration of third-party external tools in Virtual Learning Environments (VLEs) and social networks enhances the flexibility and the ease of customisation of successful systems such as Moodle, LAMS and Sakai. However, the integration problem entails a set of technological and political decisions that should be considered by the agents involved in this process [1]. Several authors and organisations have proposed different ways to deal with the integration problem. Some of the most representative approaches are: IMS Learning Tool Interoperability [2] (sometimes called Full LTI), a complex specification to integrate web services in VLEs; Basic LTI [3], a subset of the Full LTI specification that allows a lighter integration of web applications; the Wookie server [4] that enables the integration of W3C widgets and OpenSocial compliant tools in different platforms; and the GLUE! (Group Learning Uniform Environment) REST-based architecture, as an evolution of [5], allowing a loosely-coupled integration of tools developed with multiple technologies.
This paper analyses the main features of each of these approaches with the aim of establishing a comparison that may help to decide the adoption of some of them depending on the expected requirements. This analysis includes the number and diversity of tools that can be integrated; the systems in which these tools can be integrated; the degree of coupling involved; the richness in the communication and in the data exchanged between the tool and the system; opportunities for tool configuration; the possibility of using the same groups and roles that are defined in the platform; the development effort that must be assumed by the community of developers supporting each approach; their degree of standardization; and the security issues involved.