Ask HN: What are some good examples of startups that do "good" in the world?

Preferably technological startups that have managed to become profitable. Although early-stage/funded is fine too.<p>After reading a few of the inspirational submissions today it got me thinking about startups that have succeeded in solving a problem - either with the environment, society (education or otherwise), or something similar, and have managed to become profitable in doing so.<p>Any ideas?