"...Master Foo, why have you shown us how to paint a watercolor picture?"
"I have done so because it is an excellent illustration of how not to think about mashup Web applications. An anti-pattern by analogy."
"Ah. So you are saying that we should look deeper than the screens. Look at the data and the functionality that needs to be integrated first. Then worry about creating the visuals of a website?"
"Precisely. Unfortunately, very few developers will bother to do that."
See also: Sir Tim on mashups@en