Oliver Marks provides a good overview of Knowledge Plaza on ZDNet.
From the post:
Knowledge Plaza is a relatively new offering in the enterprise collaboration space and offers a very sophisticated set of tools aimed primarily at knowledge workers, and whose development has been influenced by a very large international consulting company. This product is essentially a seriously powerful and secure hub around which you can aggregate both internally created and stored content, as well as material from the entire internet, which can be tagged and contextually stored…. More here