Here are a couple of links about real non-profits (charities, as opposed to early stage startups) and twitter:
- 10 Twitter Tips for Nonprofit Organizations (Change.org)
- And now, Twitter philanthropy (Christian Science Monitor)
- Betsy's Blog: How some nonprofits use twitter
I also want to highlight Beth Kanter's blog on "How Non-profits can use Social Media" which is about twitter and all the other aspects of Web 2.0 and social media for non-profits.