By Randy Mitchell   Editor’s note: This is the first article in an occasional series covering the turbulent world of social media for businesses. We’re calling this series The Social Sandbox. This time we dig in to the shifting perceptions of LinkedIn.   The vitriol is pulsating from the comments. A highly vocal section of the social community is up in arms and they are storming the castle from all sides.   “What happened to my LinkedIn?” “I thought this was the PROFESSIONAL network.” “When did LinkedIn become Facebook?” “I hope Elon Musk buys this network and shuts it down.” “If anyone wants me, I’ll be on GlassDoor.” “#LinkedOUT”   Why is LinkedIn under fire from the people who used to cherish it as