Mashups exemplify the creativity afforded by Web2.0.

A mashup is a hybrid web application that combines data from external sources with bespoke logic to create a synergistic outcome. Most big name sites like Yahoo, Amazon and Google (as well as smaller players like Flickr) are offering access to their data streams through the use of APIs (Application Program Interfaces). Developers can use an API to gather data and incorporate it into their own applications.


The results:
http://www.liveplasma.com/
Uses info from Amazon to visually represent the connections between artists and films etc.

http://www.housingmaps.com
Mashup of Craig's list apartment search and Google Maps

http://grant.robinson.name/projects/montage-a-google/
A simple idea using Google's image library

http://www.dynamite.co.uk/local/
8-way UK specific mashup


Flickr mashups
http://metaatem.net/words/
Simple, easy, brilliant

http://labs.systemone.at/retrievr/
Lets you express yourself in a basic paint application in then trawls the web for images that are indicative of the colours you have drawn in

http://krazydad.com/colrpickr/
A similar one to the above, but nicer in other ways

http://www.quasimondo.com/tagnautica.php
Enter a word and it will display the most commonly related words from Flickr tags

http://randomchaos.com/games/fastr/
A simple game using the Flickr API


Further reading
http://googlemapsmania.blogspot.com/
A list of google map mashups.
HBO recently did one to promote its new series of the Sopranos by showing where key events in the plot took place on the streets of New Jersey. It also streamed relevant trailers into the speech bubbles within google maps.

http://www.webmonkey.com/webmonkey/06/08/index4a_page2.html?tw=commentary
Try this for a few more Flickr mashups.

http://flickrnation.com/
This guy's unofficial, but popular, blog

http://del.icio.us
A different approach to 'search'. Rather than Google which uses algorithms to find stuff it thinks you might like, delicious and similar sites (digg and squidoo) use humans to tag up online content so what it shows you is totally relevant information.

http://diggdot.us/
Delicious is also being mashed up