As of October 2006, the Yahoo! Maps show more detail for certain provinces than the other mapping services. In many cases, maps are lacking local street names. The Yahoo! Maps site has one unfortunate characteristic: if you scroll on the map or change the zoom level or do just about anything else, it adds a URL to your visited page history and that means that your browser's Back button will cycle through all the iterations of the map before it returns to this page. As a result, you may want to open the Yahoo! Maps links in a new window or on a new tab.
Please note that to use the new version of the Yahoo! mapping service, you have to click the "Get a New Map" button the first time you see it. After that, the links should work properly.