I have this huge dumbness I need to clear up. I am not sure under what circumstances (all?) IP addresses can be seen.
When you send an email from a web based email service such as hotmail, gmail? Can it be seen by the email recipient?
When you post to a blog in the comments section? Can it be seen by the blog owner?
When you post on a forum (I realize forums may vary), can the forum owner/admin etc.. see your IP address?