#BullyMovie grassroots campaign (Twitter)
The goals of campaign were to drive awareness of the launch of "Bully," a documentary on childhood bullying and to build a community against bullying. Here's how the campaign was implemented on Twitter:

The folks behind the #BullyMovie campaign had the lofty goal of creating an organic trending topic (#BullyMovie) in one day. This means 1 million tweets needed to contain the hashtag #BullyMovie. They stuck with the core message of the film: 13 million kids in America will be bullied this year, and 3 million of those kids will be absent from school due to this bullying.
Then came Katy Butler, a 17-year-old high school student who took the campaign personally and took it upon herself to create her own campaign on Change.org, where she asked her community to petition and stand alongside the film (despite its R rating). Her community grew to nearly 500,000. These two missions converged on March 27, when the campaign achieved its goal of 1 million tweets in a 24-hour period.
Why this is one of the best social media campaigns of 2012:
Fundamentally, the message pulls on heart-strings. However, it was very strategic and tactical to take this message to social media, where the filmmaker could truly reach the target demographic. Some might call the success of the campaign serendipitous, but it was a pure awareness ploy that was extremely successful. It serves as a prime example of how Twitter, as a network, can be used to amplify a powerful message.
Source: Mashable