What is a Mashup?
A mashup is a web application that combines data from more than one source into a single integrated application.
I came across an interesting article on pg 16 of InformationWeek magazine by J Nicholas Hoover, that discusses a potential mashup application. I thought it was a nice example of a useful mashup.
Example:
Salesforce.com and Google are developing an application which integrates an onlione slot machine game (Harrahs) which is built with Google App Engine, with Harrah’s VIP guest site hosted on Force.com, and using Salesforce,com data. This application would allow the VIPs to use the slot machine game on their iGoogle page. Harrahs could book the awards and track how perople respond to the game.
Web 2.0: Who, What, Why, How 