Fear of their potential power has pushed seed AI development along unusual lines. No one can ever be sure that their clever inhibitors and blocks will not be overcome by a burgeoning transcendent mind. Limitations must be as inherent and fundamental to its nature as possible to be trusted. For this reason a great deal of work is done trying to develop the most intransigently inefficient systems possible.
One of the old standbys, neglected before the Fall but being more thoroughly, if still cautiously, explored, is biological super-brains. Compared to the digital, biology has a host of disadvantages when it comes to hosting a mind. It requires more space per functional unit, has a slower signal, and even needs food. Even with nanomedicine, the volume of brain matter that can be sustained is not much larger than a human body.
As the size of any brain increases, the time required for a signal to go from one end to another also increases, limiting its integration with itself. Depending on the brain's structure, this results in either a typical conscious mind with greatly expanded subconscious functions, or a loose gestalt, with smooth gradients between consciousnesses.
The only current living example of a super-brain of brain is Jerry, located in a special bunker on Luna. Jerry is one of the first kind, an essentially human mind with an immensely powerful subconscious. Despite being human-like, Jerry lives a necessarily unusual life. He spends the majority of his time asleep, when the signal delays between sections of his brain seem to be less important, and he can mull over questions posed to him when awake. In his waking hours he spends most of his time browsing the mesh, watching all forms of entertainment and eschewing intellectual pursuits.
Plot Hook: Jerry's handlers are pleased at his lack of ambition and use in giving reasonable answers to odd questions, but the project is considered a minor failure nonetheless. To make up for budget shortfalls, they have begun hiring out his dreaming to the highest bidder. PCs can pay for Jerry to give an answer to any question, although they may not understand his answer.