A big reason geospatial technologies didn't enter the popular consciousness before Google and Bing is that they weren't easily used by laypeople. Now that has all changed - but we are still putting together web mapping sites that are difficult to use: too much information and too many tools. Why should someone have to know how to use an "Identify" tool, for example? See Peter Batty's talks on neogeography and usability, and take his advice to heart.
If you make it useful, people will come, and they will contribute. It can't be solely the domain of "GIS professionals" - there aren't enough of us to get this stuff done by ourselves.
But look at Wikipedia and Open Street Map. If we make it useful and usable, the general public will contribute their expertise and our geospatial information will be constantly updated.
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