One of my favorite clients, the Sisters of Notre Dame de Namur, California Province (snddenca.org) just had an exciting Web 2.0 moment.
Sisters from all over the country are supporting those suffering in Zimbabwe, sending 10 lb boxes of food and supplies along with letters of encouragement. The response from their members there - "We want you to know that your gifts have been the lifelines that are sustaining the Sisters and maintaining the food banks to provide food for the people around them."
In their latest enews, they described their Zimbabwe aid project and asked for $39 donations to help mail aid packages. A former member of the community in another part of the country read the email and posted a message about the SNDs and Zimbabwe on a Labrador Retreiver chat board entitled "39 dollars - is hope worth it?". Using Google Alerts, the organization was informed of the posting, read it and posted a response.
As you can imagine, this brought their message to a whole new audience via a community member, not a member of the organization requesting assistance. This was very exciting for them to witness not only the power of "word-of-mouse" but to see how supporters of their work can pass on their message in a passionate way and reach audiences they would normally never touch. Another example of the potential of personal/person-to-person fundraising that many of us are working to help nonprofits understand.
Bottom Line: You CAN trust your supporters to deliver your message in effective ways, just give them the tools, some language and then let them speak in their own voice. You may not control their specific wording, but the message is more powerful coming in their personal voice than the most carefully crafted organizational message.