Social media documentation of the protests in Ferguson has been a huge part of the story.
Many people have been following along with the situation in Ferguson via twitter, livestream, etc., and sharing information in realtime. This has been especially important because there was a media blackout in the city and because many media sources were initially not covering the story.
Check out this article documenting the social media response.
Social media has also been instrumental in coordinating solidarity protests around the country.
The primary hashtag being used is #Ferguson. This hashtag has been trending nationally (with some fluctuations) since the first night.