a client of mine told me that he uses a website that manages mailing lists to keep track of clients All subscribed in his case, But the possibility for this website to promote spam borthered me.

I went to the website looked at the start page and then left. End of story.

To my utter discomfort I received a message from the website in my mailbox addressed to me without me confirming clicking or anythinging on the site.

I have done some reading about this and have realised that a website can do a couple of things to get your browser to divulge a email address.

I use Firefox and IE and for interest sake I visisted the page in firefox to see if I get another mail from them.

All of this is only relevant to me as I would love to know how to prevent this from happening?

Some background:
My local mail server uses 3 blacklists and I have just added spamcop as a 4th.
I use spailator to filter rubbish - but I feel outlook 2003's junk filter is better as it.
I have a IPcop firewall and url filter to try and block ickky pages and adds.