actually, it’s the other way around for me. my inbox is the center point of my digital communications. if it’s not there then it doesn’t get my attention–even copies of my phone calls route to my inbox. rarely do i have the time to browse all of the forums to which i’ve posted.
the manner in which i would integrate a forum and a mailing list would be to route all messages between both applications–completely bi-directional. as opposed to simply notification of replies to particular posts. iow you would “subscribe” to the whole forum. this would afford full interaction and “browsing” of a forum via an email client. which would more likely breathe life into rather than suck the life out of a forum, imho.
i know many people who prefer email over forums and minimize their use of forums for this reason–exactly the kind of behavior that does sap the life out of a discussion group.