Electronic forms of communication have created a sea change in long-established methods of archiving for archivists, researchers, and scholars alike. This paper starts with a definition of a letter as a form of communication and briefly touches on epistolarity and the porousness of letter writing. It then examines archival complexities inherent in electronic forms of communication such as time, volume, fluidity, context, mutability, ethics, access, and preservation, and how these factors affect archivists and archiving as a practice. It ends with a discussion of the ways archivists can evolve to meet the challenge.