Use A Mushup Site To Chack Local Information

I am not use social networking site very often because I do not used to contact people a lot, especially I am not use cellphone to surf online. But some social networking sites are very useful, Checkin Mania is one which combines Google map and other 3 social networking sites information, like Foursquare, Gowalla, Grightkite. I do not know what purpose of this site, I use it to check some local information on the map, like local store, hotspot, station. Just use mouse to drag small icon to somewhere on the map, it displays information in sidebar.