A redoubtable law department GC, recently arrived from a major law firm, takes the position that the law department should do whatever helps its clients. He was glad to handle stock option processing and contract administration, for example, because lawyers do it better than anyone else in the company.
I disagree, and attack those activities as quasi-legal (See my post of July 21, 2005 that criticizes law departments that do quasi-legal tasks.).
The difference is that a law firm will do whatever its client asks it to do, because its partners thereby make more money. A law department, with fixed resources and only a certain set of talents, must be more picky, and must home in on core competencies (See my post of Aug. 13, 2006 about core competencies.) and eschew quasi-legal tasks. The view of a law firm and a law department are not commensurate.