I found out Google is bringing me readers who are interested about mashups.
Here's one SlideShare presentation about MashUps
You can see the Wikipedia's definition but if you want mine...
Mashups are web pages that collect information from other web pages with help of RSS feeds. They might be some sort of RSS feed readers optimized for some people but they can contain also completely new content (like where crimes happen in your neighbourhood).
One famous example in Finland is Ampparit showing news. Another example showing popular things in Twitter Twopular.