Social media is a dangerous thing. Let's all be honest here, we have all shared something on social media we may regret. It could even be a comment you made when you first joined and tried to act cool. We are now all realizing that those post are coming back to haunt us. Administration at companies will search social media to try and find something they do not like or can come back and hurt the company. No one wants that to be the reason they do not get the job.
There have been times I have wished social media was never invented. That way no one would loose a job or never get hired for a past post. Come on, I cannot be the only one who thinks this once and awhile. Maybe you have other reasons, but this is on the top of my list.
My only advice is that you try and be careful of what you post. You do not want to miss you opportunity of becoming the CEO of a major company because of a post from when you were in college.