In the business world, cannibalism refers to a new section of a company "eating into" the revenues of an older section of the same company. Competing with yourself is a Bad Idea, unless the old technology is obsolete, and needs to be phased out anyway. A transition to a "new business model" may cause this buzzword to pop up.

Example: When sgi sells rackmount multiprocessor Linux servers that compete in the same space as their IRIX server business, that's cannibalism.