I implore the maintainers of event- and opportunity-related email lists to use RSS instead. Get a free blog at “Blogger”:http://www.blogger.com or “WordPress.com”:http://www.wordpress.com, post your notices there, and let the interested subscribe to or unsubscribe from the feed as they like. Keep the email lists for the RSS-illiterate if you must, but let the tech-savvy turf the email-list cruft from their inboxes.
Every week during semester, I receive an email newsletter from the postgraduate association at my university. It’s called “UMPAnews,”:http://www.umpa.unimelb.edu.au/news/umpanews.html and while it’s seldom of interest to me, particularly because I live around 8000km from campus, I don’t want to unsubscribe because sometimes there is a point of interest, or notification of some genuinely important event.
My digital life is littered with such lists, and with people whose job it is to notify groups others of events and so on, by email. Every day, at least several such emails, only partially relevant, reach my inbox, along with all the personal and business communication that I really want and need to read.
Email lists are _not_ the most effective way to disseminate the kind of information that they tend to carry: event listings, calls for papers, and so on. Often the volume of messages from even a weekly list can be great enough that one ceases to care, and ceases to want to read them. One creates a filter, the messages get sent automatically to a folder, and they are never read again.
Do yourself and your content a favour, maintainers: switch to RSS for delivery!