This text below is an excerpt from a Burton Group report I wrote ~5 years ago (titled “Blogs, Wikis, and Beyond: New Alternatives for Communication and Collaboration”); it seems particularly relevant in light of the recent WikiLeaks etc. developments
Stay Circumspect: Verba Volant; Scripta Manent
Blogs and wikis make it easy to capture and publish information on the Internet and in more constrained contexts such as intranet workspace discussion forums. The Latin phrase in this section heading is often translated as “the spoken word evaporates; the written word remains” (the phrase literally means “spoken words fly away; written words remain”), and this is especially true in an era when anything published on the Internet is likely to be both saved indefinitely and readily searchable.
Even security through obscurity—using obscure website names and page addresses—is a porous plan as hypertext tools (e.g., automatic trackback reference generation) increasingly can bring content intended for small, private audiences into the purview of automated searching/indexing services. Blog and wiki authors need to be mindful of the fact that document-based discourse is a very different context from other modes of interpersonal communication. What authors say can and probably will be used against them, especially if it is said imprecisely (e.g., fraught with potential for misinterpretation and perhaps zealous overreaction) or in a way that constitutes defamation (e.g., inviting legal recourse).
Incidentally, the context for the Latin adage in the section heading needs to be reconsidered in these days of stringent record-keeping regulation, podcasting, smartphones, and other inexpensive devices that can be used to record conversations (and later transfer such recordings to computers, whence they can be readily published): Even spoken words can no longer be assumed to evaporate.