MarkerManager v3 | written on:  2013-02-24 12:39:08  
How it Works: The MarkerManager places its markers onto a grid, similar to the map tiles. When the user moves the viewport, it computes which grid cells have entered or left the viewport, and shows or hides all the markers in those cells. (If the users scrolls the viewport beyond the markers that are loaded, no markers will be visible u...continue reading