Just a Gwai Lo fun within prescribed limits [?]

Every now and then friends ask why they can't send email. The usual answer these days is that your IP is on a spam list. I've been using the DNS Stuff tool, Blacklist Mastering System™. This morning I used SpamCop's blacklist tool (for some reason, I forget why) to find that a friend's IP was blacklisted. Generally the solution is to contact your ISP to let them know that they've been listed as a spammer and to get them removed from the blacklist. I usually use whatsmyip.com to find out what my IP is at any given moment.