Still, it does me very little good when what I want to know is how to walk somewhere. Out here in the wilds of Montreal's West Island, there are many streets without sidewalks, or with sidewalks on only one side of a street. There are also numerous parks with paths through them (and this matters in winter, when the paths are the only plowed -- and therefor navigable -- way through the park), and sidewalks that take shortcuts between streets.
One simple example of this is the fact that Google Maps shows a trio of dead-end roads a few blocks north of my house. What they don't show is that these roads are all connected by bicycle and walking paths, and form a convenient shortcut when walking to the store.
In many ways things are worse in the city centre. There are numerous alleys between buildings that are never shown on the urban maps, but which one can walk or ride down, often saving a block from one's trip. There is also our famous underground city with its huge numbers of paths, tunnels and connecting buildings, none of which Google maps.
All of this would be useful information to have, but I can't really blame Google for not providing it. After all, Google isn't a cartographer. They buy their geographic information from numerous suppliers, and no one bothers to collect walking information to resell.
That doesn't mean it can't be collected though. What is too expensive to do when one is a cartographic information company is not necessarily too expensive when one can harness thousands of enthusiastic volunteers from the internet.
So, today's idea is to build a web-site that lets folks edit Google map overlays in a wiki-like manner. The site would allow for the upload of data from GPS units, or let people draw directly on the maps. There would be ways to add annotations to, for example, distinguish between a hiking trail, a sidewalk and a back alley.
The resulting user-created maps could then be displayed with a Google interface, and could even export a similar API so that folks could build upon the data presented.
If one ended up being quite lucky, then Google (or a cartographic service) might buy out the web page. Even if this did not happen (and having a business plan that requires being "discovered" by someone with deep pockets is seldom a good idea), I suspect that there are probably as many uses for user-created mapping services as there are for user-created text services, and the huge number of extant wikis show just how popular the latter are.