We've added an online georeferencing tool based on the NYPL Map Warper. http://warp.worldmap.harvard.edu. Try it out. Documentation coming. This makes it easy to get scanned maps georeferenced and loaded to WorldMap or any other GIS system.
WorldMap is adding new ways to bring in map data from other systems. Now it is possible to add ArcGIS Server REST and WMS layers to your map. REST layers are not returning attributes yet, but soon they will.
This is just the beginning of WorldMap <-> ArcGIS integration and opens up thousands of layers which can now be brought directly into WorldMap without having to first download them.
Those with sharp eyes will notice that the "alpha" has dropped from WorldMap URLs and rather than displaying an amazon URL one now sees a Harvard domain. Sites which were originally created on the AfricaMap platform will revert back to their original domains on cga-5.