Yahoo groups has instituted another policy without informing its
users. They are using web beacons (cookies) to track users
OUTSIDE of Yahoo's sites. You can opt out of this program by
going here:
http://privacy.yahoo.com/privacy/us/pixels/details.html
After you click on the "opt out" link, pay attention to the next
page. The gray button that comes up CANCELS the opt out, so don't
click it.