While I agree with Nancy Baym and Steve Jones that a medium is incapable in itself of destroying friendships, I want to add that, in my view, characteristics of email can independently influence the communication process to some extent: --The permanence or relatively long-lasting imprinting of words can sometimes affect people more deeply than words uttered in passing. Along with nonverbal softenings or qualifiers, people can more easily come back and say they weren't so serious about the opinion, or even that they had changed their minds. With asynchronous conferencing and listservs or even logged synchronous writings from chat or IM's, the rereading of the words can possibly affect people differently than just hearing the words out loud. --As several people have mentioned, reading the contrary thoughts sent to everyone on the list could provoke embarrassment as well as intellectual disagreement or anger. For this reason, among others, I choose not to receive an individual's emails to a list of people whenever possible. Actually I hope my postings here on the air-list do not in any way disrupt pleasant colleague relationships I may have established in the past. :-) Do we have research on negative sentiments or disagreements expressed f2f vs. email? I know we have some good experimental studies comparing liking and self-disclosure for the two modes.