Somehow I feel obligated to do this now. So, for you experts out there, you can go ahead and ignore this message. Being on the Internet can be very helpful, but at the same time you can cause yourself, and others, a lot of headache. I do not like to call people ignorant because we all had to learn how to do things right at some point in life. If you don't want people to know about you, then don't post it.
News groups are the most common places where spammers get people's emails from.
One way to avoid you being tagged as a recipient is to change your email address in such a fashion that it makes it invalid - yet, adding instructions in your message itself on how to send you email using a proper address. Email collecting software isn't that smart, trust me. So any information you put out there will be known for a while by others. These are a big NO-NO on the net. Always direct it to whoever it's destined to.