Bogus email addresses (Score 1)

We have a simple domain, being ddd.com, and we get between 10,000 to 100,000 emails a day, most of them spam. Only about one quarter of one percent are actual valid emails. It was a very annoying problem as it chewed up large amounts of bandwidth until we installed Mail Marshal which drops emails based on a white list and then kills of spam on top. YaY for Mail Marshall...