Twitter users more likely to share happiness than sadness

Contagious emotions: Researchers investigated the sharing of good news and positive content on Twitter.

Emotions spread like a virus in the Twittersphere, say American researchers who have observed that positive joyful tweets are more contagious than negative ones. 

Some users of the Twitter social network are more likely than others to be contaminated by the "good news" virus. In other words, happiness is a contagious feeling.