Simply put, a mashup is a Web application that uses information from multiple sources in order to create one cohesive and user-friendly tool which allows someone to access data from multiple locations with one look saving them time from doing extra research.

Mashups can be intended for the general public or specific business or industry, they can also be either web-based and accessed from any computer or server-based and accessed remotely. Mashups should not be confused with embedded data. Simply inserting a YouTube video or a map from Google Maps onto a website does not make it a mashup. Rather, the creator(s) of the site would need to find a way to layer or modify the data in order to make it a mashup. For example, the site WikiCrimes is a wiki-style site where anyone can go and make edits in a Google Map to show where crimes in their area have taken place. They can then add details about the crime so that people who are interested in the area may look at it and find out what types of crimes take place there.