Paul Schwartz (UC-Berkeley School of Law) has published The Future of Tax Privacy, 61 Nat'l Tax J. 883 (2008) (Symposium on Technology, Privacy, and the Future of Taxation).  Here is the abstract:

This essay considers the past, present, and future of tax privacy. Regarding the past, it took until 1976 for the concept of tax privacy to be explicitly established in statutory law. Congress established this concept in Section 6103 of the Internal Revenue Code, but has also made it subject to numerous exceptions. In the present, much personal financial information is now accessible out of the tax context and is regulated by other statutes and regulations. This result has made the area of tax privacy somewhat less exceptional today as a regulatory area than in the past. Finally, in the future, tax information in the electronic age will be subject to the same critical issues, such as those involving data security, as other personal information. In conclusion, tax information remains important, but is increasingly subject to the same forces—legal and technical—as other personal information.