phishing emails

[Bob Brennan]

On 5/26/05, STYMA, ROBERT E (ROBERT) <stymar at lucent.com> wrote:
> > hi community,
> >
> > I must warn you that somebody uses the fedora mailing lists
> > to get email
> > adresses and to send them phishing emails. I recieved a html
> > mail with a
> > fake ebay login which links to
> > http://140.121.196.32/phpBB2/db/index.html
> >
> > do not enter your email login
> >
> > regards,
> > vassilios kotoulas
> >
> There are a bunch of ways to collect emails.  In some cases, just
> visiting a site can expose your email address. 

Pardon my flame (or my ignorance?)... but how would "just visiting a
site" expose your email address??