This article is from 2010, back when the edns-client-subnet [1] draft wasn't even published.
I believe most CDN's are now whitelisted with Google's and OpenDNS's edns list, so you'll much better results. also see edns-client-subnet demo [2]
[1] http://tools.ietf.org/html/draft-vandergaast-edns-client-sub... [2] http://news.ycombinator.com/item?id=4174512