Radian6 was launched in 2006 by Chris Newton & Chris Ramsey in Fredericton, New Brunswick, Canada.  The system is designed to help organizations monitor and engage social media activities. It is a system designed to help companies monitor and engage social media activates. The product is used by marketing, communication and customer support professionals.
On March 30, 2011, Radian6 was acquired by SalesForce for $326M. It is now part of Saleforce Marketing Cloud product suite.
Radian6 helps social media managers uncover influencers, track and measure engagement and determine which conversations are having an impact online. It contains integrated social media, CRM and web analytics. The system provides analysis and streamlined reports with a workflow capability.
Product Features 
To read the full product review go to TopTenReviews
With Radian6 you can build a social media campaign based on keywords and phrases. The campaign activity is then tracked using widgets that that show an overview. Gadgets include:
River of News
watch the defined keywords flow into the system in real time from posts on social media sites such as Twitter or Facebook.
A visual that allows you to see top words surrounding your product or brand. This helps you watch what is trending.
Charts are used for analysis and can be used to drill down to the specifics.
It is easy to share data with other users via HTML, XML, PDF or email.
The tone of a post is important and Radian6 can assign a sentiment so that you can sort posts and focus on the ones the user needs. Sentiment definitions can be modified to provide the sorting the user needs.
Help, Support & Documentation
Training tools, help documentation, tutorials and support are available and are of quality. Live chat is available and small and medium business are provided with an account manager who can help you get started.
Radian6 is a very useful tool and is of high quality. There is a learning curve because this is an extensive product and the user must have an understanding of the social media world. The user will find great value in using this product and it will provide time saving capabilities. Companies that have active products and social activity will find it invaluable.