Twitter providing support during overwhelming natural disasters is the best use of social media I've seen by far. Most recently, Indonesian tech-savvy people are taking things into their own hands using Twitter in support of relief efforts.
In the past month, Indonesia has experienced earthquakes, volcano eruptions and tsunamis. People acted fast in tweeting aid supports, causing a powerfully viral effect from the locals and online community. Twitter providing support of Indonesia's disaster relief efforts is proving to be just what is needed to make an immediate difference.