This book constitutes the thoroughly refereedpost-workshop proceedings of the Second International Workshop on Semantic WebCollaborative Spaces, SWCS 2013, held in Montpellier, France, in May 2013, andthe Third International Workshop on Semantic Web Collaborative Spaces, SWCS2014, held in Trentino, Italy, in October 2014.

The 6 revised extended papers presented were carefullyreviewed and selected from 10 submissions. The papers are grouped in topicalsections on challenges in collaborative spaces, modeling collaborativecommunities and the role of semantics, semantic MediaWiki communities, andexploiting semantics in collaborative spaces.