How to collect email address of site visitors

[builder]

How do I collect the email addresses of ALL visitors to my web site? I'm not talking about forms to subscribe, etc. I'm talking about a script that can automatically capture the email address of any and all visitors. There must be a way, because I often get email from sites I visit even though I didn't enter ANY information at that site. I'm not interested in spamming visitors, I simply want to send them a one time message thanking them for visiting and inviting them to return.

Thanks

[jeffmott]

How do I collect the email addresses of ALL visitors to my web site? I'm not talking about forms to subscribe, etc. I'm talking about a script that can automatically capture the email address of any and all visitors.You can't.There must be a way, because I often get email from sites I visit even though I didn't enter ANY information at that site.Some sites collect your information and then sell it to spammers. This is also unavoidable, unless you thoroughly read the privacy policy in every place you submit your information, and plan to take legal action against those who do promise not to reveal your information but do so anyway.

Sometimes mail is also sent to random addresses. For example, AOL, how often have you tried to register a name with AOL (or AIM) and it not be already in use? You could send messages to random AOL addresses, and more times than not the address would belong to somebody.