Social Media and the Impact on PR

I am working in the PR industry only since last year in August, took many classes, I am still a student and now I got my first agency internship in January at Weber Shandwick in Austin. Besides that, I am doing an independent study for school about social media and how it impacts public relations as an industry, how PR is and will change through the use of social media, an how the industry will look in a few years. I want to know how people use social media in PR to get positive and maximum exposure for their clients.