Can social media be used as a tool by one individual to successful push change in society?

Social media can successfully be used as a platform to get a single voice heard by the use of its basic function, to share material. By uploading any one thought to Facebook or Twitter, it has the potential to reach a global audience. If one individual makes a call for a change in society on social media, all it takes is for one person to agree for the message to spread. As soon as one friend clicks 'share' or 'retweet' on the message, it reaches a new audience. For every subsequent share of the individual's thought, it massively spreads the message to new geographical locations as well as classes of society. With more people spreading one message, it has a public backing and fuels discussion. With many people sharing the ideals of the first individual, it has greater chances of action being taken. Take for example a petition. If an individual posts their own petition on their Facebook page, the use of sharing on the social network will help this petition reach more and more people - perhaps more than it ever would have. It may easily, and quickly reach the number of signatures it needs to get considered - and to make a change in society.