How are they computing "brand value" ? MSFT's market cap is ~$184B, and GOOG's is ~$127B. They're just using some subjective measure?
I found page 6 of this pdf: http://www.millwardbrown.com/Sites/Optimor/Media/Pdfs/en/Bra...
The summary is that it's the NPV of the brand's future earnings, multiplied by the fraction of that revenue due to the "brand" itself and not location/price/etc (this is estimated by market research experts), multiplied by an estimate of future growth (more market research hand-waving).