A lot of well-meaning organizations promise not to sell their mailing list, but will "trade" it with other organizations, which amounts to the same thing. I realize that to the organization, this database is an asset and looks like $$$. But donors do not want 10 pieces of unwanted mail to show up in their mailbox for every dollar they donate, no matter who sends the mail.

I'm not sure exactly what "anonymous donor" really means. The 3 charities on my donation list that had a specific checkbox for "anonymous donor" are: Tubman Family Alliance, Minnesota Emergency Foodshelf Network, Feeding America (Second Harvest). Maybe you can figure out from their websites what information they actually keep. As long as they don't bug me or increase the number of other organizations bugging me, I don't much care.