George Bernard Shaw Quote
If you have an apple and I have an apple and we exchange these apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas.

Or – If you have a CD and I have a CD and we exchange these CDs then you and I will still each have one CD. But if you have an mp3 and I have an mp3 and we exchange these mp3s, then each of us will have two mp3s.

And therein lies the problem nobody has figured out yet.