I can understand the points about social aspects at work, but some of the content concerning more tangible business benefits seems too idealistic. e.g. "I suddenly remembered that I’d seen a communication exchanged between these two guys.." -- how often do you happen to remember seeing that kind of conversation? Imagine these tools are barely making a dent in the amount of duplication and lack of "metaknowledge" that goes on in any mid to large sized company. And that comes with the oft-cited costs of distractions, etc. Or am I just using them wrong?