1.) http://www.mapsexoffenders.com/
I like this mashup because I like to know who my neighbors are. It's also going to be useful for when I want to find an apartment. Sex offender locations are also a good indicator of what property value in an area is like. This mashes up the Meghan's Law database with GoogleMaps
2. http://www.findthatpet.com
This mashup is great. I'd be really sad if my dog ever got away, and this would be a great tool to help me find her. They mashed up Google Maps and their pet reporting system to help people post that a pet ran away, and to post if they found a lost pet.
3. )http://www.scholr.co.uk/
Uses Amazon E Commerce to find a book you like and relate it to other books, similar to last.fm. I like this app because I read a lot and like to find new books. Unfortunately it's British, so I only use it for reference, if I want to buy a book I have to find it myself.
