I subscribe to a few IETF-centric mailing lists, including atom-syntax, that are hosted at the IMC; Recently, I posted an Atom-related suggestion (see also here) but the posting never showed up. I checked with Paul Hoffman, who does a fantastic job of running the site (competently-run mailing lists aren’t that easy to come by), and he told me I’d been auto-unsubscribed because my ISP had decided, deferring to the SpamCop Blocking List, that the IMC’s SMTP was a spam source and (temporarily) blacklisted it. This is the second time in a month that I’ve had legitimate emails get bounced this way. I re-subscribed from my Sun address, but apparently, to quote Paul: “If you trust spamcop, you will continue to lose your mail randomly without knowing why.” If you read the SpamCop page linked to above, it looks like SpamCop would agree with Paul’s analysis. Anyhow, now I’ll find out if my ISP will stop applying this filter to my email, and if not, I’ll have to find a new ISP.