Take a sort of "post-singularity" society, in which the net has become sufficiently complex that no one really understands entirely how it works, and has begun to do stuff on its own - not to the AI level, just "stuff".
Add in the tech to record memories. You have a fuzzy internet with uploaded personalities floating in it.
Call the net entities "loa", and have them "ride" people via cybernetic brain implants. Basically, to become a doctor, you don't go to med school, you carry a medical loa. Knowledge is preserved and advanced through generations directly.
Obvious questions to explore - how much of the person survives the upload process? Just experience, or personality, too? How does it affect the ridden person's mind to carry loa on a regualr basis? Do uploaded personalities remain distinct, or do all the doctors merge into a sort of big doctor spirit? How available is the upload tech? Is there a central body regulating uploads? Is is expensive enough to remain available to a select few only, or are there uploads across the economic spectrum (this last raises the possibility of digital sacred prostitutes being riden by an electronic Ishtar). What effect do all these minds have on the already self-motivated net? Does this system move form a sort of polytheism to a monotheism as the personalities merge into a single cybergod?
Are the loa self-aware enough to have thier own goals? How much to they cahnge after death? What kind of impact on innovation does this sort of structure have - does relying on the loa mean that the society just keeps refining past techniques and not inventing new ones?
Who can be ridden? Anyone? Or do the loa have preferences, creating a new specialist class/vocation? Just how prestigious is it to be ridable? Do we end up with a middle class of "horses", with a rich upper class who can afford autonomy, and a poor underclass who can't effectively work?
What happens when the process goes wrong? In keeping with the voodoo theme, I posit the occasional frying of a "horse"'s mind, leaving the subject a zombie - little mind, but a body that can be put to menial tasks.
I might try to fire off some microfic in this setting later, but I wanted to throw this out there.