Given a topic or (more tractably) the name of a company or institution, find people who are good sources to contact.  Approaches might include looking on “About us” pages for the company/institution and finding people mentioned there, looking at LinkedIn or Twitter profiles or people quoted in previous coverage of this topic, with links to the original source material.  A good method of expansion once given a “seed” set of possible contacts (whether from the organization’s web site or previous articles) would be to find people or organizations whose names co-occur in online documents—and then people or organizations whose names co-occur with those, etc. [For journalists]