Yahoo is now using something called “Web Beacons” to track Yahoo
Group users around the net and see what you’re doing. It’s similar to
cookies but apparently oh-so-much-more insidious.
Here’s the spot for you to opt out and review their updated privacy
statement…
It’s easy to opt-out (just click on the link about half way down), and it won’t adversely affect your account. I urge everyone who values their privacy to do so.
What cookies are is just a way of storing variables client side, and accessing them on a next http request.
So to say it’s ‘similar’ to cookies is not correct. What yahoo does is simply use cookies to access the personal information (probably only a user_id) and feed the information back to yahoo on the affiliated websites.