The descriptions of social media that I've found just describe the various tools that people use to share contents and to connect each other. Some introduce the concept of collective intelligence. I propose the following definition:

Social media are digital media based on neutral computer networks. Locally, they assume the form of instruments and practices that individuals use to share content, often something they have generated themselves. Globally, if a sufficient number of individuals and connections are involved, they show the phenomena of self-organisation, emergence and unpredictability typical of complex systems.

I elaborate on the fundamental aspects of this definition in this paper: Elements for a Social Media Theory. I would like to discuss and validate my arguments with the help of people attending the Lift Conference.