1) Black listing - if someone in your IP neighborhood sends spam you can be silently blacklisted by Comcast, AOL, some random crazy zealots running a blacklist

1) Black listing - if someone in your IP neighborhood sends spam you can be silently blacklisted by Comcast, AOL, some random crazy zealots running a blacklist that other random people choose to use… et.al. and people stop getting your mail. Good luck getting unlisted. Wasted hours. Sometimes it's futile. 2) Spam filtering - If you are the sort of hacker that publishes their email address in order to interact with the community, and you become popular with spammers, then it is difficult to beat Google's spam filtering on the hundreds of spam you will receive each day. Until a few years ago I used to run my own servers and corporate servers. Nicely trained bogospam filters (this is work and involves the brain killing activity of reading borderline emails to categorize) got most of it with little risk of resource consumption failures. SpamAssassin got some of the remainder, albeit with some risk of exploding, but spam still got through. Those same addresses now let about 4 spam per year through the Google filters. You can't beat them. Your sample size is too small.