I popped in to the Location Intelligence conference for mapping professionals the other day and saw a few very interesting new tools, such as DataPlace, a service set up by the Fannie Mae Foundation (and free to access) that takes publicly available demographic information, such as census data, and lets you display it in a variety of useful formats, including maps.
It is very easy to get absorbed in browsing this system, surfing for average mortgage prices in your community, tax return information, the proportion of single-parent families, and so on. There are also nonmap ways to slice and compare the data. It's a treasure trove of information for anybody who's interested in marketing their products or services. It's also great fun to play with.
While the base maps the system uses look just like Google's maps, they are not. Instead, they are built by the mapping tools company Placebase, which, if you're looking to build out a commercial mapping system, offers better options. For example, you don't have to run the Google logo on Placebase maps, you won't suffer from the bandwidth limitations Google puts on maps used in mashups, and the company layers data in a way that makes zone maps (like DataPlace) possible. Yet the end user controls are exactly the same as Google Maps, so users don't have to learn a new way of moving around their maps. The downside: Unlike Google Maps, Placebase tools and services are not free.