Spammers buy lists of millions of E-mail addresses and IM screen names. Harvesting programs gather up these addresses wherever they can find them online, in chat rooms, on message boards, from chain E-mails, and registrations. Many of these addresses are old and don't work. If you reply, one of two things happens. You either have sent a reply to a fake address spammers have used to send the E-mails from, or you have now let them know that your address is a good one and you will receive many more messages. They will even sell your address for more money, since they can now promise that you have read the spam messages you received.

While your E-mail service provider may ask you to forward spam to their TOS (terms of service violations address), you shouldn't bother. Instead, use a good anti-spam program.

How private is the message you are sending? Are you willing to have others read this message or forward it to others without your permission?

E-mails get misdelivered all the time. And sometimes the people we send them to share our communications with others without asking us first. (This includes logs of our chat-room discussions and of instant messaging.) The courts allow others to read your E-mails under special circumstances. Don't ever say anything in a cybercommunication you wouldn't be willing to allow someone else to read. We always tell people not to say anything they wouldn't write on a postcard they send through the mail. If you're going to share something very private, it's best to use the phone or person-to-person communications (obviously, only with people you know in real life).

When anyone applies for jobs or internships the recruiter will sometimes "Google them" first--that is, run a Web search. We've seen many cases where old messages people posted when they were much younger and didn't realize would turn up in an online search cost them an internship position or a job. (It's always a good idea to "Google yourself" regularly and make sure nothing turns up that you would be embarrassed about or that gives away personal information about you online.)

Think Before You Click "Send"
One of the biggest problems online is that no one thinks between their "brain dump" typing and clicking "send." One of my friends, after she says something rude or inappropriate, smiles and says, "Oh, did I say that out loud?!" That's because we all think rude and inappropriate things but generally don't say them out loud. There's a filter between what we think and our mouths called being polite.

Generally, this filter kicks in when we're looking someone in the eyes and envision how they would respond and how others around us would respond if we said what we really wish we could say. But when we sit in front of the computer, there are no eyes to look into--just us and the computer monitor. And just as we can say outrageous things in our diaries, typing them online seems private. It's also fun to say things that you know you shouldn't say. Wouldn't it be really cool to tell that office bully off? Or tell your boss how stupid you think he is? Everyone has things they wish they could say. But, usually, when we break the rules and say them, we wish we could take it all back.

But you can never really take it back. And when you send or post something online, it lives on forever in archives, caching, and other places. Like the Energizer bunny, it keeps on going and going and going.

At the least, wait 24 hours before you send a message you know has some large potential repercussions. That may give you enough time to calm down and look at the issue from a more rational perspective.

Write That Message, But Don't Ever Send It
If you've just got to get those thoughts out of your head, though, set up a file on your computer (but not your workplace computer!)--a kind of "brain dump" journal, where you can save things you wish you could say but know you shouldn't. Sometimes, just writing them down is enough to make you feel better. You can always go back and read what you wrote later and see how you feel about it. Most of the time, you probably will be happy you never sent it. Sometimes, you may forget what made you angry to begin with.

Parry Aftab is a cyberspace lawyer, specializing in online privacy and security law, and she's also executive director of WiredSafety. She hosts the Web site aftab.com and blogs regularly at theprivacylawyer.blogspot.com.

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To find out more about Parry Aftab, please visit her page on the Listening Post.