Daniel Nations has provided a nice explanation of a mashup:
“A web mashup is a web application that takes information from one or more sources and presents it in a new way or with a unique layout. The key driving power of the Internet is information, and a mashup is an application that takes that information and shows it to you in a unique way.”
When I was reading this definition somehow the ‘newspaper’ came to my mind. The only thing is, it is a solid product. The web is becoming a social space. So you can find many websites opening up programming interfaces (API's) that allow developers to get at their core information.
Google Maps is a good example. Google allows developers to access their maps through API's. The developer can then combine these maps with another stream of data to create something new and unique.
The name "mashup" is derived from the idea of combining data from two or more sources and displaying it with a unique look. However, newer mashups sometimes only use a single source of information for example TwitterSpy.
