Since this topic is general I am trying to find some examples for this to better answer this question. I would like to focus on one part of the world which has the highest number of bloggers in the world after Japan and probably one of the most complicate political systems in the world: Iran. The country has faced a lot of political challenges challenges in its very long history. One of the most interesting ones has happened very recently during the latest presidential election. The 2009 Iranian presidential election was held on 12 June 2009 in Iran, the tenth presidential election to be held in the country and many protestors believed a fraud has happened and the results was not based on true number of voters and their choice. Protestors was beaten by the revolutionary guard and "Basij" forces. Pictures and videos were takes by people and was broadcasted using their cell phones. Twitter, youtube and Facebook was used heavily by Iranian protesters.
In general, the increasing penetration of new communication technologies and social media into everyday life has attracted a growing interest in the social, economic and political implications of these technologies. At Western democratic societies the use of blogs and twitter is mostly around the cool subjects such as sports, wine tasting or the literature. The bloggers in Iran are mostly interested in social or political debates. Perhaps for this reason, the use of blogs and social media is substancial in developing countries such as Iran.
In 2009 Iran witnessed a political upheaval in the aftermath of the presidential election in which the Internet was utilized effectively by the political opposition. News and videos of police brutality and repression were uploaded online, including onto social networking sites, in what was called the ‘Twitter Revolution’. Expectations rose on the capacity of new media to bring about democratic change in Iran. I'd like to suggest that, firstly, new media has helped ordinary citizens and the political opposition challenge the government’s monopoly of information and propaganda. Secondly, I suggest that new media have paved the way for the emergence of a global public sphere for Iranians across the globe. Also looking at the social and cultural impacts of the satellite channels which have been an ongoing source of concern for the Iranian conservative regime and the number of text messages that was being sent everyday tells me that social media is not only a tool for communication but also influences people by sharing ideas. 1
When Jack Dorsey, Evan Williams and Biz Stone founded Twitter in 2006, they were probably worried about things like making money and protecting people's privacy and drunk college kids breaking up with one another in 140 characters or less. What they weren't worried about was being suppressed by the Iranian government. But in the networked, surreally flattened world of social media, those things aren't as far apart as they used to be — and what began as a toy for online flirtation is suddenly being put to much more serious uses. After the election in Iran, cries of protest from supporters of opposition candidate Mirhossein Mousavi arose in all possible media, but the loudest cries were heard in a medium that didn't even exist the last time Iran had an election. 2
The 2009 presidential election attracted global attention and gave rise to hopes for progressive change in Iran. However, the events that followed cast doubt on the realization of these hopes (Esfandiari 2010).
No matter the social media is being used as the main vehicle of mobilizing political actions, I believe social media is playing a vital role in new democratic movements in Iran since one of the biggest fears of dictators is from the people who understand their true power by uniting and social media is helping people to understand how powerful they are! Thank you twitter!
1: Online journal of the virtual middle east: http://www.cyberorient.net/article.do?articleId=6187