Whether a component of an Internet communication is classified as "content" or "envelope" information determines in large part the privacy protection it receives under constitutional and statutory law. Courts and Internet law scholars have yet to offer a means of determining the content/envelope status of unique aspects of Internet communications-from email subject lines to website URLs. As a result, data with the potential to expose every website, every Internet file downloaded, and every email sent by an Internet user may be unprotected under current law.
This Article develops a legal framework for distinguishing content from envelope information in unique areas of Internet communications. Drawing on a practical analysis of the structure of the Internet and an evaluation of relevant common law and Fourth Amendment doctrines, the Article proposes that electronic information that can reveal the underlying text or subject matter of an Internet communication must be classified as content. The Article identifies several areas in which application of this principle is necessary to resolve difficult questions about the legal status of an Internet communication, and gives, for the first time, a comprehensive account of the content status of Internet communications, from email body text to website IP addresses. The proposed framework provides a judicially manageable and normatively attractive means for courts to determine the legal status of novel communications technologies, present and future. Ultimately, resolving the content/envelope distinction has the potential to clarify other unanswered and controversial questions in Fourth Amendment and statutory privacy law.