Interesting column from John Gapper in the FT today. Here he's talking about Jonah Peretti, founder of Buzzfeed:
His insight was that sharing works differently from search. Search is a way to discover information, whereas sharing is prompted by emotion. People read all kinds of material but they mostly share stories or videos that create positive reactions, such as laughter; or actively negative ones, such as anger.
Well worth a read - even registering to read - if only to get to the final line, with which I heartily concur.