Now that law firms and corporations are just getting their arms around e-discovery and how to implement the proper retention policies, voicemail is entering the scene. What is making voicemail such an easy target for discovery is the advent of technology which allows the use of the internet as a means of distribution, most commonly voice-over-IP or, voIP. With additional technology, people can receive voicemails as e-mail attachments and can even have voicemails transcribed into text automatically. Once in e-mail, a voicemail's life expectancy is much longer and creates yet another feeding ground for those looking for the 'smoking gun'.
A article posted on the Lexis web-site gives a very good primer on the issues surrounding voicemail discovery.