Why the BPO industry?

I had always been on the lookout for useful sites to help me when I was looking for a job in the Business Process Outsourcing industry, something that can make the picture a bit clearer. So far, I haven't seen one that was able to help me fully understand the concept of a BPO. So I guess that now, being in the industry, I have some sort of responsibility (eherm) to enlighten my fellow jobseekers' path.