Very simply, a Mashup is when you take similar or common information from two separate sources and present it together in a new solution. In technology, a mashup is a web application that combines data from more than one source into a single integrated presence, thereby creating a new and distinct web service that was not originally provided by either source. Mashups originally referred to the practice in pop music of producing a new song by mixing two or more existing pieces. Content used in mashups is typically sourced from a third party via a public interface leveraging different technologies such as RSS, SOAP, REST, etc. Other methods of sourcing content for mashups include Web feeds (e.g. RSS or Atom), and screen scraping. Many people are experimenting with Mashups using Amazon, eBay, Flickr, Google, Microsoft, Yahoo and YouTube.

For example, many Mashups are popping up for real estate websites. The cartographic data from Google Maps is used to add location information to real estate data, thereby creating a new and distinct Web service that was not originally provided by either source. It provides a more useful tool for people looking for homes. Mashups are getting popular with the evolutions of SOA architectures, web services and Web 2.0 technologies.

Mashups and portals are both content aggregation technologies. Portals are an older technology designed as an extension to traditional dynamic Web applications, in which the process of converting data content into marked-up web pages is split into two phases - generation of markup "fragments" and aggregation of the fragments into pages. Each markup fragment is generated by a "portlet" or “web Part” web component, and the portal combines them into a single web page. These web components may be hosted locally on the portal server or remotely on another server.

There are many types of Mashups, such as consumer mashups, data mashups, and business mashups. The most common mashup is the consumer mashup, which is aimed at the general public. Examples include GoogleMaps, iGuide, and RadioClouds. Data mashups combine similar types of media and information from multiple sources into a single representation. Business mashups focus data into a single presentation and allow for collaborative action among businesses and developers. The potential use cases for mashups are as wide and varied as the Web. Some of the most common early use cases included mapping, video, and photos. Some real Mashups that exist today are: 

• WikiCrimes is a wiki-style web site where users can report crimes by placing pins on a GoogleMaps-based map. The Web site classifies crimes as robbery, theft, or other;
• Flickrvision is an example of a mashup made using Flickr's API;
• qflick is a mashup using the Flickr API as well as the Cooliris embedded wall;
• Travature is a travel portal that has integrated airfare meta search engines, wiki travel guides, and hotel reviews. It allows the user to share photos and discuss experiences with other travelers; and
• Digg is a place for people to discover and share content from anywhere on the web. It is a mashup of various news web sites controlled almost entirely by the users of the web site.

InfoMesh Technologies specializes in designing, combining and implementing Information Meshes and Mashups to create dynamic and rich internet solutions.