Twitter for Social Media Marketing has become quite popular with social media marketing professionals.
Ron Knight  discussed in a article some ways in which Twitter can be used in your social media marketing campaign.
1. Sharing Links to Items of Interest
2. Building Your Network
3. Build Relationships within Your Current Network
4. Re-Distributing Content from Your Blog or Website
5. Get Involved in Live Tweeting Events
6. Pitching Stories to Journalists on Twitter
7. Communicating with Your Team
8. Brand Monitoring
9. Acquire More Votes on Social Media Websites
10. Hiring People
11. Build Your Personal Brand
12. Streamline Electronic Communications

Read the full article here on Twitter for Social Media Marketing