I need to update my LinkedIn, I'm never on it.
I honestly thought the entire point of it was like a resume sharing sight. Your personal profile is like an online resume. I mean yes you can make connections and stuff, good idea to connect with people you've worked with and might want to hire you elsewhere also. However, I don't understand the point of posting. Maybe posting that you are hiring? Maybe posting that you're willing to take on new clients? Maybe posting to talk show your values as an employee?
I guess perhaps posting to flex what a great employee you are and how people should hire you, or something related to your professional interests. I don't know if I think of it as social media. It's like if you apply for a job, the profile your potential future moss might want to look at.