JISC has released Content Clustering and Sustaining Digital Resources.
Here's an excerpt:
This eBook presents case studies from 11 digital projects managing digital resources for Higher Education. One strand of case studies look at the skills required to build and sustain digital collections, with a focus on how universities embed digitisation as a strategic activity within their core work. The second strand draws on case studies examining how digital silos can be broken down, as users demand increasingly sophisticated resources that cluster or aggregate related content from different areas of the Internet. The projects were funded under the JISC eContent Programme for 2009-11.