Social media monitoring Definition
Social media monitoring is the active monitoring of social media channels for information about a company or organisation.
Several different providers have created tools to facilitate the monitoring of a variety of social media channels from blogging to internet video to internet forums. This allows companies to track what consumers are saying about their brands and actions. Companies can then react to these conversations and interact with consumers through social media platforms.
Examples of companies that provide social media monitoring platforms include Radian6 and NetBase. Though they have different approaches to the problem, both Radian6 and NetBase provide their clients (market researchers and brand managers) tools that allow them to examine conversations that are happening on social media that are relevant to their brand.
For instance, NetBase provides "scorecards, " which take a quick look at how well a brand is doing on social media, and a "workbench, " which gives companies the ability to dig a little deeper into these questions. Radian6, among other services, provides a number of different reports that cover everything from sentiment, to influence and to competitive analysis. 
People complaining to friends about their health or waiting times at hospitals is nothing new. But as more choose to do so on internet forums and social networks such as Twitter and Facebook, they may be surprised to learn that hospitals and healthcare professionals are “listening in”.
Organisations such as the Care Quality Commission, the UK's health and social care regulator, and several NHS hospitals are starting to trawl the web for clues about where they need to investigate low standards or direct extra resources.
Social media monitoring is becoming common in the private sector, as companies listen out for complaints about their own services, or those of competitors, to help poach customers.
In the public sector, “eavesdropping” on online conversations can tap opinions from people who may not want to fill in a formal survey form. 
Washington County Public Schools to monitor social media in schools — Herald-Mail Media
Not long ago, school system officials found out about a student at a local high school posting threatening comments through a different social media-monitoring company that alerted authorities, according to Wilcox.
Energy and the Wealth of Nations: Understanding the Biophysical Economy
What are the top china social dashboards and monitoring tools?
I work for Brandwatch - excuse the self promotion, but we do cover Chinese language social media (both traditional and simplified) and are one of very few tools who have coverage of sites such as Weibo - you can find out more about our Chinese coverage here: