Lessons From The Outsourcing Primer:

Some consider business process outsourcing (BPO) to be information technology (IT)-enabled business processes.
BPO has to be a contractual delegation of an ongoing process to an external contractor and not be used strictly for individual projects.
Though BPO is seen as the emerging market, it antedates information technology outsourcing (ITO).
BPO has evolved into a diverse set of markets that are separated into three categories: finance and administration; operations; and sales, marketing and customer care.