Yahoo is now using something called “Web Beacons” to track Yahoo
users around the net and see what you’re doing and where you
are going – similar to cookies. Take a look at their updated privacy
statement:

http://privacy.yahoo.com/privacy/us/pixels/details.html

On the very same page in the section “Outside the Yahoo!
Network”, you’ll see a little “click here” link that will let users proceed to another page which allows
you to “opt-out” of their new method of snooping. Users who are security and privacy conscious are highly recommended to do this.

Once you have clicked that link, you are opted out. Notice
the “Success” message the top the next page.

Be careful because on that page there is a “Cancel Opt-out” button
that, if clicked, will *undo* the opt-out. Feel free to forward this
to other groups.