Vote: Best Do-Gooder on Twitter

He tweets to his 4 million followers about issues and facts relevant to his namesake foundation, which aims to protect the environment and the people and creatures that inhabit it.

Follow him:@iansomerhalder

The model and designer updates her 15,700+ followers with the latest news on FEED, the nonprofit she founded in 2006 to fight hunger.
Sample tweet: "Help us spread the word that hunger is a real issue in the US by tweeting #FEEDUSA 50 Million Americans need our support! @FeedingAmerica" (See it here.)
Follow her:@laurenbushtweet

Bush supports women’s reproductive rights in one tweet and an education nonprofit in the next. Plus, she’s not afraid to take on Twitter trolls.
Sample tweet: "This is incredible! Less than $1,700 to go and we’ll have built our THIRD @PencilsOfPromis school. Can we do it?!" A day later, she and her 800,000+ followers did. (See it here.)
Follow her:@SophiaBush

As the founder of Every Mother Counts, a campaign that aims to make pregnancy and childbirth safe for moms around the world, Turlington tweets stats and facts about global maternal health to over 100,000 followers nearly every day.
Follow her:@CTurlington

The actor and environmentalist only tweets to his 7 million followers about causes close to his heart.
Sample tweet: "Did u know less than 2% of charitable donations go to eco issues? Thrilled to partner w/ @ChristiesInc for #11thHour." (See it here.)
Follow him:@LeoDiCaprio