Investors often buy stocks by news and information in social media.  Social media is where have some things good and bad. It is important if  you could value information in them. Price eats those  make  increasing its price by The theory of efficient. It could come back its fair if it is no where to go.

Best Buy -  BBY droped around $12 right way last thursday (Jan - 16 -2014),. You could lost your money in that way.  You should combine a technical analysis and fundamentals.  for example, We could buy BBY at back points (back points are points that price could back) if  it has a good fundamentals 

This is a technical analysis of BBY