I am a big believer in knowing your target audience, and that applies to social media as well. Thus that leads to bounce rates either being extremely high or relatively low.
Most people see high bounce rates from the social news sites, because by nature, they promote "read the article and run" kind of situations.
If you or or clients are looking for success from Social Media, then target places where your audience congregates. Say for example your client sells cookware, well then write articles for the social news sites dedicated to cooking, participate in cooking forums, talk to cooking bloggers and build a profile in the cooking social networks out there (there are some!) LOL By utilizing social media sites that are more relevant to your niche, you'll lower your bounce rate.
I think gauging whether or not social media produces high click rates or not, is relative - and highly dependent on which social media sites you target.
I really believe that you need to strategize when it comes to social media, have a plan and choose the social media site you want to participate in, and have a plan for each and every one. Do the research, and know each sites pros and cons, and you're likely to have lower bounce rates.