Mashups are an exciting genre of interactive Web applications that draw upon content retrieved from external data sources to create entirely new and innovative services. They are a hallmark of the second generation of Web applications informally known as Web 2.0. This introductory article explores what it means to be a mashup, the different classes of popular mashups constructed today, and the enabling technologies that mashup developers leverage to create their applications. Additionally, you'll see many of the emerging technical and social challenges that mashup developers face.
Online social networking is all the rage. In this article, learn how to build a social network with Google Maps, Twitter, Groovy, and Ajax. By combining a Google Map with location information that Twitter exposes, you can create a mashup that allows people to view Twitter in light of a particular location. The simple application this article builds lets users view a map of their Twitter friends — a geo-view of their network.