A gross Whuffie score looks the same to everyone viewing it, but a weighted Whuffie score is subjective. This meta-Whuffie takes into account right-handed Whuffie (the amount given by people you like) and left-handed Whuffie (given by people you dislike). Another variety is pity Whuffie, given to those who are down on their luck.
In Down and Out, some judgments based on Whuffie are automatic and require no conscious thought; the same technology that allows brain dumps is used for weighting and for finding interesting things. As brain dumps allow machines to carry consciousness, the machines can do the thinking for the people and allow them to know automatically.
There are few details in the book about how this system actually worked; most of the explanations given are very general, like this one: "Whuffie recaptured the true essence of money: in the old days, if you were broke but respected, you wouldn't starve; contrariwise, if you were rich and hated, no sum could buy you security and peace. By measuring the thing that money really represented — your personal capital with your friends and neighbors — you more accurately gauged your success".
A person with a score of 0 is just as capable of giving and revoking Whuffie as someone with a score of 1,000,000. The person with the million-point score would be invited to a lot more parties and shows and other exclusive and elite events, while his bottomed-out counterpart would get dirty looks from people on the bus and would probably not be allowed into any reputable clubs or restaurants. But both of their opinions on somebody else would count for the same amount of gross Whuffie.
Like all economic systems, Whuffie has effects that seem undesirable to many. For example, it might tend to favor popular speech at the expense of public discourse, and it could be frequently uninformative: if a person has a high Whuffie score, is it for guitar playing or auto repair? However, both of these are already the status quo under the existing capitalist system, and the concept of weighted Whuffie helps make better decisions on a person-by-person basis, and thus is more flexible than rating someone by their bank account. Also, the Whuffie system might keep a public history of how each person's Whuffie was earned, unlike the secret origins of other people's money in a capitalist system.
Howard L. Myers wrote of a similar system based on admiration in his story "All Around the Universe," written between 1967 and 1971.
Whuffie is mentioned in Doctorow's Eastern Standard Tribe, but appears to be in the general sense of building reputation.