[douglaswlance]

That's not how statistics works. They're classifying groups, not individuals.

[emiliobumachar]

Really? Could you please elaborate?

I would think they are classifying each individual into one of many groups, each group being an arbitrarily delineated social class. If that's true, than Mr. Buffet would indeed have the potential to be misclassified, because his behaviours ("features") are atypical of people as rich as him.

[ada1981]

They may also look at the socioeconomic status of the people you associate with and make inferences.

[press-any-key]

"... socialeconomic group of users ...'