browse.delicious is visual browser that let users explore and browse through a sample data-set of del.icio.us to see and understand the connections and relations of its entities

Atlanta, Boston, JFK, LA, and Chicago so far

Find pubs in London by location, tube or postcode using Google Maps

Discusses putting together a Map API that lets you embed a map into your website, a data source, and ways to get around cross-domain restriction in order to create a mashup of your own.

“Online mapping is evolving into a historic nexus of disparate technologies and communities that is changing the fundamental use of the Internet, as well as redefining the concept of maps in our culture.”

create, share, and tag your own Google Map w/o resorting to the Google Maps API.

rough-around-the-edges Google Maps/Weather mashup

Seattle 911 responses mashup w/ Google Maps