In a post on the Index Data blog, Sebastian Hammer nicely sums up the value of finding the expert when it comes to information retrieval:

It’s easy to find the Einsteins, the Darwins, the Freuds. Dig a little deeper, and you find the people, themselves giants, who stood on their shoulders. But what if you want to find the person or team who knows the MOST about a very specific type of protein, about building Firefox Plugins, or about adjusting the wheel bearings on a certain kind of vintage motorcycle? This seems to happen to me all the time when I am digging into something for work or play. If you get deep enough, looking for documents doesn’t sate your appetite, and you start to look for the masters of the domain — to see what they’re up to; to get into their heads, to ask them questions, or to hire them.