Mashups can be defined as "a website or web application that seamlessly combines content from more than one source into an integrated experience". Marshups are an excellent example of the increasing variety of things search engines can do and what you can do with search engines and the different kind of experiences provided by Web 2.0.
For example by means of Google and Yahoo APIs, a broad range of data that was coded as to an exact geograhic location was integrated with maps and aerial images.
Check out:
ws1.inf.scd.yahoo.com/maps/applications.html
[Only registered and activated users can see links. ]
Very good sites but if you have a inexperianced coder who decides to pull information from sites with dodgy code the site will actually slow to a hault
Since you started this thread, may I ask what's the difference between mashup and feed?
Anyway, the link that you've given lead to an empty blogger page