Google’s Fusion Tables is a place where you can store tons of data. You can then with couple of clicks visualize that data instantly on Google Maps or as Intensity Map. You can also view it as a Line, Bar, Pie, Scatter diagrams.
Columns with locations are interpreted automatically, and you can adjust them directly on a map if necessary. You can apply filter and aggregate tools for more selective visualizations.
There are lots of tables in Google’s Fusion Tables which are publicly accessible which you can use to start mapping.
Once you select a table and select the “Visualize—–>Map” option, you have the option to Export to KML, Get KML Network Link or Get Embeddable Link for your website or blog.