Google maps are really cool. At their most basic, they enable users to find something, zoom in, get directions, view satellite imagery, etc. But with the application of a bit of skill, you can do so much more. Custom markers, pop-up descriptions with photos, automatic plotting of locations based on addresses... and so much more.
For example, when used in conjunction with an online business directory, we can automatically plot each item on a map, complete with descriptions, contact info and an image or logo. Each type of business (restaurants, golf courses, etc.) has their own marker image and users can choose to view just one category at a time if they so choose. Like we said, it's really cool.