Internet covers many areas of people's everyday life (Barabasi, 2003). First it was Internet growth, which allowed information distribution amongst millions of users. Then it was increased communication and social fabric, the relationships. Collaboration has been exploited at an unprecedented level. The Web is a vast field of research that links wide-ranging research areas such as knowledge representation, tagging objects, reporting and many other issues that arise during the creation of shared information systems and collaborative development.

Collaborative tools should help to achieve the principle of one of the pioneers of collaboration, Douglas Engelbart (Bieber et al, 2002): "The World is getting more and more complex, and we need to work together to collaborate. Our survival depends on our ability to work together more efficiently, more intelligently, to get collective solutions. Computers - used in a correct way - can help us to overcome this challenge."

Collaboration technologies allow you, amongst other functions, to share favourite web pages with your partners, to find documents and email messages quickly using tags, to write about experiences in a personal website (blog), to show a community what you are doing in real time and work on a shared document in a team project. All these new features are the result of a revolutionary way of sharing knowledge online within an organisation or company, which has been described as a participatory Web. This article provides analysis of collaboration from a technological point of view and describes the most relevant tools and techniques.