What is Social Media?

Andreas Kaplan and Michael Haenlein define social media as "a group of Internet-based applications that build on the ideological and technological foundations of Web 2.0, and that allow the creation and exchange of user-generated content."^[2]

What are the ideological and technological foundations of web 2.0?

Web 2.0 sites allow users to do more than just retrieve information. Instead of merely 'reading', a user is invited to 'write' as well, or contribute to the content available to everyone in a user friendly way.
Wikipedia

 Traditional Media

Traditional media such as print publishing, TV, film and radio can be described as passive media,  authored and delivered as finished content package that accepts no further revision. The audience receives the package in it's completed form and passively digests whatever it contains. The reader may have thoughts about the content but these thoughts will have no effect on the package.

Web 2.0

Web 2.0 is dynamic and delivers an adaptable news feed that changes with circumstance. The content can be dynamic because it responds to a changing data feed, such as weather pages, tide times and energy feeds. Or the content can be dynamic because it adapts or reflects user interaction, this can be a simple as adding user comments or can be more complex such as Wikpedia which revises pages on user instruction.

Technology

Technology
What powers instagram
The shift from relational databases to unstructured data.

Authorised Content

Social Media platforms are walled gardens that can only be accessed by authorised users.