What types of business applications are most often used for social media?

The top 5 applications most often used for social media applications are:

• Citizen Engagement/Services Communication Applications: there are a number of approaches that are being used to improve citizen and services communication using social media tools or community interaction portals to allow organizations to socialize their ideas. In addition, blogs and social networking tools like Facebook have become effective ways to rally target audiences around key conversations of community relevance.
• Employee Engagement: Use of social media for employee engagement/internal communication is a major focus for organizations in both the private and public sector. For example, blogs can be a very effective communication channel for management to get key leadership messages out, but also invite employees to engage in the conversation, post questions, add comments, etc. A popular form of employee communication internally is using low cost Twitter look alike tools like Yammer (recently acquired by Microsoft).
• Learning & Development: Social media tools are very effective in supporting internal training, and learning and development needs. Popular uses include YouTube or other video services to set up lower cost training tools, supported by social networking engagement tools so employees can continue to ask experts questions, use of wikis and social networking tools are also very effective tools to support learning and development practices.
• Customer Services: Many government organizations are using Twitter for issuing alert services on transportation, safety or health messages to reduce call volume traffic.
• Collaboration: Organizations use collaboration and social media platforms like IBM Connections/Collaboration Suite, Igloo, Jive, and Microsoft Share Point  to share project information, departmental communication, manager/employee communication centers.