On July 28, proponents of a Referendum in Washington state asked a U.S. District Court to protect the privacy of the people who signed their petition. The case is Protect Marriage Washington v Reed, 3:09-cv-0546. The case was assigned to Judge Benjamin Settle, a Bush Jr. appointee. On July 29, Judge Settle issued a Temporary Restraining Order, preventing the names from being made public until the case is decided. See this story.
There has been few precedents on whether the names and addresses of people who sign petitions should be considered a public record. Some states provide by law that the records are not public, but most states do not. The petition in this case is to prevent a new law from going into effect, to provide for civil unions for same-sex couples. No one knows yet if the petition has enough valid signatures. Proponents submitted 138,500 signatures. They need 120,577 valid signatures, so it seems somewhat likely the petition will fall short.