I'm currently spending my Sunday evening cruising through LinkedIn.  One of my friends on Facebook wrote that "LinkedIn is like Facebook's boring uncle" and it stuck with me.  I see where she is coming from but at the same time it's a good platform for your professional side.  Facebook, on the other hand, is where some young professionals get in trouble for displaying some not-so-professional photos.  So I don't know if I'd call LinkedIn "Facebook's boring uncle".  I'd say LinkedIn is like the front half of a mullet while Facebook is the back half; business in the front and party in the back.  They're both apart of who you are on the internet, one shows the business appropriate side while the other shows who you are outside of work.  No matter how you look at the two, it's probably a good idea to keep your mullet metaphorical and off of your head.