JoeAudette.com

I got a good kick out of Martin Fowler's post about Service Oriented Architecture, I have felt for a long time this is a meaningless word that gets bandered about all over the place. Almost anyone who is building web services now calls it Service Oriented Architecture and there is no additional agreed upon meaning to that phrase. To me it sounds like the difference between web services and service oriented architecture is that service oriented architecture means you are now using web services for everything, it does all your data access, it does all your business logic, it solves all your problems, it sounds good when you say it. 

I've usually thought of it like this

web services

are useful tool for supporting interoperability between systems
are useful for exposing data to other parties outside your company
are useful for office integration like keeping Excel documents and charts up to date (every company I know has a bunch of manually maintained spreadsheets that consume hours and hours just keeping them up to date)
are useful if you are building internet aware software, I could say Smart Clients but that is another silly buzz word though probably less ambiguous

and Service Oriented Architecture means you are doing all or most of those things

but I have to agree that Service Oriented Architecture is one of those phrases where 2 people could be having a conversation about it and think they are talking about the same thing while each has an entirely different idea about what they mean.

I also think that a lot of the early adopters who are using web services to solve every problem are going to be facing some major re-writing once the security standards for web services get worked out.