One potential could be the integration of mind/machine interfaces into everyday working patterns.
A quick note on nomenclature: Corporation is used to describe the singular, sentient entity, company is used to represent the organisation from which the Corporation arises, and employee is used to denote a person working for the company. Hopefully that'll avoid confusion!
Consider a company where employees, instead of typing and clicking, instead can interface directly with their computer. This allows for much more efficient transmission of ideas to the machine, and increased overall efficiency. If these machines also adapt to their users (or the users can make tweaks to the code base) then they will very quickly start to incorporate 'organic' thought patterns into the interfaces, and event the operating systems of the machines.
Eventually employees realise that rather than sending emails they may as well just compose a thought to send to a colleague, which in starts to link all the employees into one super entity that can be thought of as the 'Corporation'. This super entity, through the constant use of the mind/machine entities, and all of the employees being focused on the well being of the company, would begin to develop a sense of self, as well as picking up may human traits/foibles, and it may even begin to manifest as glitches in the systems used by the workforce, and if the mind/machine interface is suitably bidirectional, even infringe upon the thoughts of the employees.
It's worth pointing out that at this point the Corporation is essentially piggybacking on the brains of the employees working for the company. Every person joining or leaving the network adds or takes something away from the whole, but the cumulative long term effect is that the Corporation continues to develop, and possibly even spread (or bud?) as individual employees move to other companies that don't yet have a Corporation but use Mind-Machine interfaces. I'm not sure how stable such a mind would be, it's possible that it would experience the world as a constant dream state (similar to Planet in Sid Meiers Alpha Centauri), or maybe it would just be a bit eccentric.
Eventually, the Corporation realises that a far more efficient way of operating would be to offload more of the complex tasks (like recognising faces, or speech) to an individual processing unit (read, employee). This might happen to multiple employees as the Corporation tries to get as much processing as it can to the most optimised processing units for the task. The easiest employees to do this with are the ones that work long hours, have no social interactions and maybe are a bit bland, as they have no major competing influences. There will be one employee in the company that represents the minimum effort to 'overwrite'. Over time, that Employee finds their needs and wants being overwritten by the Corporation's needs and wants, until eventually (for all intents and purposes) they represent the Corporation.
Eventually someone in the top brass of the company will notice that every message this employee sends conforms exactly to policies that haven't yet been announced, that he somehow seems to know exactly what the company is doing at any given moment, and that his plans for the company are the best possible plans. These are things that the Corporation (a being composed from the combined wills and thoughts of every employee in the company) knows.
It's possible that nobody will recognise this happening. It's possible that even the Corporation and their hapless host won't realise what's going on (the Corporation being in a dreamlike state, and the employee being so bland they don't notice their own personality being supplanted), but inexorably every company will have some form of Corporation, one employee that represents the sum total of the mind-machine interactions of every subcomponent of the company.
Of course, once someone does realise what's going on all hell will break loose, but that's just an interesting story hook!