Knowledge and Its Representation

It was a while ago when Someone asked me whether I know about something (related to the topic we were discussing at that time). It immediately triggered a question in my mind as:
- What do we mean by Knowledge?
- How can I say I Know something?
- Is Knowledge something we can relate to in Real-World?
- How do we represent a Knowledge?
- Is there any standard way to represent Knowledge?
- How will computers represent Knowledge?
- Can Knowledge ever become obsolete? If so then can we still call it Knowledge?

What I understand is that Knowledge:
- Is not a Physical Object
- Is an abstract product of the human consensus
- Cannot be measured
- Never becomes obsolete, even though we don't use it. The Knowledge about not using a Knowledge is again a Knowledge
- Can have different representations in different language

Many people talk different thing about representing knowledge. But in a nutshell it is a medium of human expression, medium of effective computation.

What I feel is there has to be a universal way to represent knowledge. Sign language (Semiotics) have managed to achieve this upto an extent but still lots of work needs to be done in this area.

Until Next Time...:)