Problems and issues in online learning by Stephen Downes (October 2002) argues for repositories to be distributed and interoperable rather than locked away in silos. "The silo model is dysfunctional because it prevents, in some essential way, the location and sharing of learning resources." The silo model results from: proprietary standards, overly strict standards, 'monolithic solutions', a closed marketplace, 'disintermediation', 'selective semantics' and 'digital rights mismanagement'. Particularly interesting are disintermediation and selective semantics. Disintermediation (which only sounds like a good thing) is when there is no provision for third parties (intermediaries) to rate, sift, interpret or comment on the objects in a repository - i.e. one has to take the owners of the repository's word for it. Selective semantics is when people act as if learning object repositories are different from other kinds of repositories and design them to according to particular education-oriented standards (e.g. SCORM) rather than "integrated with or compatible with many other resources and services available." A more formal version of the same article (I think) is Design and Reusability of Learning Objects in an Academic Context: A New Economy of Education? published in the USDLA Journal.