Cnet doesn't 'advertise' it so to speak, they just don't take steps to prevent the profiles from coming up in general web searches. Some sites allow access to user profiles only by other registered members while logged in, but here it's in the public domain...anyone can look at it so any search engine can find it. If you're concerned for your privacy you can always edit your member profile, removing any private information and setting it to hide your real name. Note, however, that Google and others keep stored copies of older versions of webpages (caches), so the data would remain visible through other sources, at least for a while.
Regards,
John
Hi All,Why does CNET Forums see fit to advertise my cnet profile to the world?????
http://www.google.com/search?sourceid=navclient&aq=t&ie=UTF-8&rlz=1T4GGIH_enAU218AU218&q=doug+hawken+profile

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