E-Mail Capture

> Does anyone know of any software that will
> capture a website visitor's e-mail address
> when they visit your site, even if they do
> not sign up for a newsletter or anything ?

> Thanks.
I don't know what the software or technology is, but I just received an email from someone thanking me for posting on his FFA page. I never did, though I remember looking at it and reading an offer or two.

Generally I surf with my email "despammed," that is, with obvious bogus information. Lately, however, because I have wanted to respond by email without firing up my normal client, I have it in my browser.