In web development, a mashup is a web page or application that uses and combines data, presentation or functionality from two or more sources to create new services.
There are many sources for getting data (raw information). Governments are good examples.
However many of those cost and have complicated licensing. For instance SMHI in Sweden sells temperature data meanwhile our neighbor country Norway gives it away for free.
One would say what kind of application are you building and what data do you need? I would say give me some interesting data and I will do a good mashup of it. I could just plot it on Google maps for instance.
So the question is: Where can I get free data?
Note: I'm not interested in data mining using a webcrawler!
Please share your sources with me.