You don't need to keep up with anything if you use bogofilter, or similar statistics based methods, to classify it. You can do server side filtering based on ot

You don't need to keep up with anything if you use bogofilter, or similar statistics based methods, to classify it. You can do server side filtering based on other non-content things like DNS lookups, or IP blacklists, but that's just adding needless failure modes on the receive side. I don't do any non-content filtering, to keep things simple for the senders and latency down. Statistical methods are just that effective on a personal mail server level.