I think that participatory journalism has experienced a significant growth within the past few years. Its growth can be easily adjudged to a mix of facts that not only expanded the number of users that are having their ideas published and read by others, but also the span to which this type of media reaches.
As mentioned before, several factors gave place to the ever-increasing popularity of participatory journalism; freedom of speech, the globalization of social media are among others determining facts that raised normal people as leaders among a community (or in some cases of a much bigger spectrum of people).
Examples are not hard to find and present itself in a variety of ways. Perhaps among the most popular I can name the Arab Spring or Occupy Wall St., movements that were originated due to the mobilization of people through social media (Facebook and Twitter) and generated a global impact.
I do not think we realize the power that everyone of us has nowadays by just having access to social media. We can go from hero to villains and viceversa with just a few clicks. The boom has created so many new characters, in which people get their second of fame due to a Facebook post, a tweet or a YouTube video.
Occupied Wall St. Journal: http://occupiedmedia.us/