The Economist on Drucker-like knowledge workers: Thinking for a living. The most interesting part of the article (IMO) is the one that deals with how knowledge workers communicate:

how to improve knowledge-work productivity...is one of the most important economic issues of our time.” One way, he suggests [Thomas Davenport in his book “Thinking for a Living”.], might be to examine how different workers use knowledge; to see which technologies best gather and disseminate the information that knowledge workers need; and to find the workspace that is best suited to people who are highly mobile and need to concentrate a lot.

I took the liberty to put this graph I found pertinent, even though it's not commented in the article, because it shows the importance of e-mail for instance; it's a pity they did not discriminate the various forms of email (mailing-lists, one-to-one, group mailing...)

The source of this the book "Thinking for a living" by Thomas Davenport.