Back in April 2005 Paul Rademacher created the first Google Maps and real-estate mashup, HousingMaps. Itssold.ca provides a nice comparison to Paul's original real-estate map, showing how things have developed in the last five years.
Housing Maps pulled in data from Craigslist and allowed users to filter results by property prices. Itssold.ca has far more extensive filtering of your house requirements. The site uses a slide-bar to allow users to define the range of price that they are interested in. It also includes slide-bars to define the number of bedrooms, the number of bathrooms, the property size and the year built.
The information windows on Itssold.ca also shows how Google Maps mashups have developed in the last five years. Whereas HousingMaps simply included text links, Itssold.ca contains property details and photographs. Clicking on the 'more photos' link loads a photo slideshow in place of the map.
Itssold.ca also dynamically loads results directly on the Google Map. If you pan the map around map markers load to reflect your current map view. The only real omission from the site is the option to view the properties with Street View.