SOA - So what's new?

I was talking to a colleague on SOA, ESB and other related stuff that I've blogged here. He gave me a patient hearing and asked, "so what's new?" He said that all this SOA stuff was already being done in the EAI space for a long time now, even before the term SOA was coined. "An adapter is a service, right?", he asked and I said yes and went back to square one - asking myself, so what is an SOA? More importantly, what is a "service"?

[Update]
After posting on my state of mind above, I went ahead Googling for SOA definitions and reasons, hoping to find better meaning and purpose for its existence. I found John Reynolds' post "The SOA Elevator Speech" very satisfying. The perspective on SOA is that while normal integration focusses on the technical aspects, SOA does that at a business level - all services are described at a business level rather than a technical level (to paraphrase John: processing an order is a service in a SOA while updating a record in a database is not).

I hope that I am now better prepared to take on that colleague of mine.