Twitter is collecting life-changing and inspirational stories of Twitter use on a Twitter Stories [1] page launched in November 2011 [2]. One recent story describes how Twitter was used to help rescue the victim of a carjacking [3] in South Africa, another how a tweet helped a man find a kidney donor [4].
You can use the hashtag #Twitterstories [5] highlight other examples.
The photo above is by Twitter [6].