Got this from an email on on of the NAF listservs:
If you belong to any yahoo Groups this is important...
"Yahoo is now using something called "Web Beacons" to track Yahoo Group users around the net and see what you're doing and where you are going --similar to cookies. Yahoo is recording every website and every groupyou visit.
Take a look at their updated privacy statement:http://privacy.yahoo.com/privacy
About half-way down the page, in the section on cookies, you will see a link that says web beacons. Click on the phrase web beacons. That will bring you to a paragraph entitled "Outside the Yahoo Network."
In this section you'll see a little "click here to opt out" link that will let you "opt-out" of their new method of snooping.
Once you have clicked that link, you are exempted. Notice the "Success" message on the top of 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.
Also, please note that the opt-out is not user-specific - so you will have to opt-out on each computer and/or browser you use.