Jobs Mailing List

I'm thinking of designing a new system to distribute job postings by email.

Some features might include:


 * Handle 6,000 subscribers currently, scale easily up to at least 20,000 (and hopefully far beyond that)


 * Handle 100 broadcast posts per day currently


 * Postings regulated somehow so only job posts get sent to the list -- no spam, discussion, vacation auto-replies, etc. should be sent to subscribers


 * List must be very simple to unsubscribe from, through the obvious ways a subscriber might attempt to unsubscribe - i.e., attempting to send mail to the list with "unsubscribe" in the subject or top of body, using a link at the bottom of each post to send mail or visit a web page


 * List must be double opt-in -- new subscribers must confirm their email address and desire to subscribe in order to be subscribed


 * Moderators must be able to block and unblock posts from a particular sender


 * Moderators must be able to subscribe or unsubscribe a particular person

--  Pete, I'm wondering if you might set your job posting system so that job postings are used as an alternative currency. The idea being that local is good, and that posters don't want to get overwhelmed, and want high quality responses.