I just received this in my inbox:

  Hi,
  We want to let you know that in the coming months, we're upgrading
  the content you created in My Maps. All of the maps that you've
  created will automatically move to the new Google My Maps (previously
  called Google Maps Engine). Classic My Maps on maps.google.com will 
  no longer be available. You don't have to take any action to ensure 
  all your content will be upgraded.

  If you don't want to wait to start using the new Google My Maps, you 
  can begin migrating your maps today. 

   1.  Open the new My Maps. 
   2.  Click Upgrade now to get started.

  The new My Maps is a more powerful maps creation tool that makes it
  easier to edit and share maps you've made. Just like with classic My
  Maps, you can work on a map with others, save driving directions, add
  photos and videos, and more. With the new Google My Maps, you can also
  do things like: 

    •   Share your map similar to how it works for a Google Doc. 
    •   Use different colors to make parts of your map stand out. 
    •   Label your features directly on the map. 
    •   Import locations from a spreadsheet. 
    •   Organize your places with layers. 

  For more information, please see our FAQ. 


  Thanks for using Google My Maps.
  Happy mapping,
  The Google Maps Team