The key to a successful social media site is fresh, entertaining and engaging content. Post frequently enough that members are motivated to keep returning to your site. Maintain variety through different types of posts, discussions, photos and events. Go ahead, post something today!
Post something fresh. Just don't do it on Facebook, Twitter, Tumblr, MySpace, or any site other than LinkedIn.com. LinkedIn.com is social media for career-minded people and not joystick jiggling, thumb pushing people whom would allow any screwball to call his or her personal friends to ask private information about you. By the way, this is what happened to me on Facebook, and why I pulled my memberships from every social network except LinkedIn, where people ask ME for information that is CAREER oriented.