Social engagement requires more than posting information about your product or service. You need to look for ways to be helpful to people without trying to drive them to your site. Look for opportunities to build relationships first and foremost. Once people see that you're helpful they'll begin to be interested in what you do and offer, but rarely before then.

On the issue of your site, you may have some optimization/usability issues that need to be looked at. High bounce rates are indicative of improper messaging and a site that just isn't meeting visitor's needs and expectations.