Lee Lefever has come up with a good post on experts and expertise, particularly as reflected in a place like Wikipedia: Wikipedia and the Value of No Experts At All.
Let's say you're trying to learn about digestion. You can likely find an expert who can sit with you and make digestion very easy to understand. Now, lets say you're talking to two experts. Something changes - the experts are now double checking each other and looking for ways to relate their unique point of view. With each expert you add, the more accurate the information becomes and the harder it becomes for you to understand.
Lee suggests that this problem rears its head on Wikipedia. When experts attempt to speak to experts, rather than to non-experts the language and style of the dialog changes. Or when an expert provides their opinion, and then another comes along, the way the second person describes the topic will be different - partially because everyone has a different perspective and partially for reasons of ego. This isn't a bad thing. Lee wants us to remember, simply, that collective experts aren't necessarily the best way to get basic information on a topic.
The thing I see in this discussion is the value of having many communication methods. Sure, I can look up a topic on Wikipedia and sometimes get a fairly well-written discussion. But other times I'll find a mess or an argument-in-progress over the content of a given topic (i.e. the KM entry in Wikipedia). Fortunately, I can also look for solo experts or collectives that decide to put out a single voice on a topic. I could even look to print media - and frequently do so. I have to be a smart information consumer, though. And I don't know that everyone has the time or inclination to do so. The first hit on their search engine is frequently good enough.
[I could have sworn that I'd already written about this, but I don't see it.]