On News Aggregation: Added Value Facts

In CACM:  News aggregation is a common thing in the internet.  Many sites and blogs find news in their specialty areas, and the results are redistributed to different markets.   This information is often commented upon and re positioned for new readership. A value added model.  That is what this blog and its predecessors have done, first within the enterprise, and then externally.  It also seeks to provide value in small doses that are easily scanned.  What are the legal and value implications of this approach?  More on the topic.