Tinkering or thinking?
We too often start with tools and wonder what we can do with them. A large part of the Library 2.0 movement is like that. There are sites, like 23dingen that seem to promote that attitude. Learn what the internet has to offer and then use it, professionally if possible. The workflow seems to be as follows: become aware of what the internet has to offer, get used to it, and apply it. Do all that, then take the attitude of an evangelist, and your are a modern 2.0 librarian.
This is tinkering.
The idea that our work should be demand-driven leads to tinkering too. We define services in collaboration with researchers and librarians and then realize that service. Serving our customers is of course our main goal, in the end, but librarians should not jump from "demand" to "demand". What is lost is a reflection on that what may connect the services thus developed, what is lost too is a critical attitude to the foundations of a library. For example, customers tend to take many things for granted (like: libraries shuffle documents, whether online or offline, libraries offer search tools that answer questions by presenting a list of documents). A rethinking of the foundations of libraries and the resources it works with will rarely be triggered by obeying customer demands.
Tinkering works from existing "infrastructures": takes them for granted. Not tinkering, but thinking might be instrumental in changing that infrastructure in order to deliver future services with a maximum of ease. It is not that no one thinks about such an infrastructure. OAIS reference architecture, SOA, 5S and similar undertakings show that infrastructural issues are addressed in the literature. Also, the Linked Data Initiative has come with clear advice on how to represent metadata and how metadata can be re-used. Registries of identifiers are seen as essential in this context. The issues around Open Data and rights of (re-)use have received considerable attention too, and are an integral part of a solid infrastructure. That work could lead to the definition of an overall architecture and to the development of a flexible infrastructure on top which new services can be developed.
It would be advisable, I think, to retract from the demand oriented strategy and start working on the specification of a good and flexible infrastructure using one of the existing methodologies (a few were mentioned). I think it is an essential step that would make future developments less costly and increase the likelihood of developments to become stable and sustainable services. And we surely should not waste our time with 23 things, there is no inherent evil in that work, but it distracts us from the core issue: build an adequate infrastructure for the digital library.
We need to think more and tinker less.