The post is right, I think: when library people say “customer service” they can mean (at least) two different things: 1) “how can we fix staff people’s behavior?” or 2) “how can we improve the services we offer?” I actually think these two things are very related (but very different questions, I agree), and can even be taught in the same training session, or at least #2 can be touched on in a session that is primarily about #1. Granted, either can become an all day (or all week!) training.
I agree with the point in the Infoblog post that “In both cases you will want to work on the foundational elements of communication.” Additionally, it is imperative that you tie customer service to your library’s mission, vision, and strategic plan. 
For example, the Waterford (CT) Public Library’s Mission includes the goal “People in Waterford consistently receive quality library service provided by well-trained, dedicated, knowledgeable and customer-oriented staff” [this refers to that “first” kind of customer service.] The goals of the Ames (IA) Public Library’s strategic plan define the types of services they will offer. [this refers to that “second” kind of customer service.]
As most public libraries struggle to do more with less in this current economy, we often hear (or fear) “something’s gotta give.” But in order to remain relevant to our public, and prove ourselves as an essential service, that “something” must not be customer service, no matter how you define it. You can find lots of articles on customer service in public libraries. Here’s just one, from Public Libraries magazine.
So what do YOU mean when you say “customer service”? And how are you improving it at your library?