In this thesis I address challenges related to the design, development anddeployment of web and mobile technologies used to support CollaborativeSeamless Learning (CSL) activities practiced across a variety of learningcontexts. The scientific publications at the core of this thesis offer adescription of the research I have performed over the last five years, andcomprise studies involving several hundred users.My research efforts included the elicitations of the requirements for and thedesign of a number of web and mobile tools to support collaborative seamlesslearning activities. A web-based environment called CeLS was developed tosupport the orchestration of CSL activities. It was then expanded to integratemobile solutions, aimed to extend the ability of CeLS to support educationalinteractions performed inside as well as outside physical classroom. Thesemobile solutions were designed to implement learning activities that supportdata collection, personal response systems and interaction with mobile videos.The main aim of the research was to investigate how best to design tools andsystems to support students during the enactment of collaborative seamlesslearning activities, and to provide teachers with artifacts to design and assessthose. Special emphasis has been given to the exploration of approaches thatenhance the flow, reusability and sharing of learner-generated content acrossdifferent learning activities. Several studies were conducted in order to validateand assess these ideas and concepts. Various data collection methods wereused to gather data from different stakeholders during the deployment of thedifferent CSL activities. The outcomes were processed and analyzed resultingin a set of recommendations concerning the design, development anddeployment of web and mobile applications to support collaborative seamlesslearning. A software architecture including various web and mobile integratedcomponents used to support innovative CSL activities is also proposed.