I'm working on a future cyberpunk setting in which I would like to explore posthumanism as a main theme. Among some of the ideas I have I want to use the very well explored "decking" trope.
The idea is that at some point in time humanity managed to create a crude brain-computer interface, that allowed not only access to silicon machines, but also running programs using brain's terrifying processing power. Hence, Technological Singularity followed, with wealth represented by physical production facilities becoming obsolete, as with the excess processing power brute-forcing trade and political forecasts became feasible. Finally, technology demands caught up with the supply and humanity's most relevant stock is now carefully traded processing power. Countless people have been contracted to trade in the power of their brains in exchange for remuneration and it just so happened, that average level of intelligence turned out to be the easiest and most efficient to utilise.
Now, most people work by plugging in to the data processing cloud for a set amount of time. The contracts vary, with a significant amount of people enjoying games etc. while being plugged in and trading in a set percentage of their brain activity, some having only passive reception of data with minimal amount of interactivity left to the brain's owner. The most extreme (and well paid) employees would lay comatose while nearly 100% of their brains are being devoted to stock trading or running AIs. Of course, majority of the population would unplug for at least a couple hours every day to enjoy real life. That also assumes that entertainment and similar services moved on to the new medium, Neuromancer-style.
That would leave only the misfits living mostly in the physical world - the geniuses, the morons, the weird and strange minds that are too different to be a mass resource. They would too be able to plug in, but extracting processing power would be too inefficient for them to provide a reliable source of income.
What would be the social and economical implications of such a world? Keeping in mind that Joe Average literally sells his brain time to someone else and his mediocrity and predictability is prized and promoted, what sort of man would he be? What sort of values would he hold, what would he believe in, what would he want in his life? How would he spend his time off and how would he spend his time? I'm looking for a kind of stereotypical Everyman definition, the same way we recognise the idea of "mid-range corporate employee" or "middle-class big city dweller".
In response to comments: I imagined the transition to processing power as an aftereffect of general transition towards virtual life. Of course main expenditures would still be rent, utilities, food etc. However, a person might forgo all earthly things and basically occupy a coffin rigged with life support gear, while living his life in virtual environment. Now to create such an immersive environment the power of brains of others would need to be utilised, effectively balancing the processing power budget. The excess would be utilised towards human advancement - even if that just means more sophisticated virtual goods (experiences). Generally, it would seem, that at any given point participants in this "cloud brain" structure would be divided into suppliers and consumers, with one creating processing power for the others. Apart from human consumption I would imagine there are AIs who require immense number of brains, but enabling technological singularity and - being sentient - having an attitude towards human suppliers. Of course, different variations are possible, such as Matrix scenario where AIs would harvest power by oppression or a more caring one, where proliferation of brains is actually achieved by AIs genuinely forging a better future for humanity.
I would imagine in a world that derives wealth from processing power, other resources such as food, construction materials and energy would be harvested automatically - using AIs and self-sustaining plants. Work for the incompatible geniuses would be most likely centred on frontier areas - where network is not sufficient to sustain automatic AI or it is not feasible - such as space exploration, colonisation. I would imagine that such a civilisation would be probably halfway to becoming a Type II, according to Kardashev scale.