It works for me! If I follow that link I get a Google map that I can zoom in/out, move the map around, show as a map, satelite, as Google Earth view within the web page or directly in the actual Google Earth software. If I have a Google account & I'm signed in then I can edit the map (ie, put markers on it) in the My Maps mode but only because I've been put on the list of authorised collaborators, which, as I said, is done by invitation.
Ahhh, sweet New Zealand.
Have a look at this tutorial.
http://earth.google.com/outreach/tutorial_mymaps.html
Not everyone will want to put their specific address but even a town or city centre would do. If enough people can get their heads around it then it will do the same job as the old map otherwise it is just another internet moment that will pass into the big null server in the sky.