Thought I'd give it a try. There is a new "Plot KML" button under QSO Archive
Selecting this gives you a choice of grid square sizes.
I selected the 4-digit grid map as the majority of my contacts, from JT65 have the grid as 4 digits. In a standard JT65 QSO you exchange 4 digit grid squares, eg CQ VK1DI QF44.
Google Earth starts and displays grid squares you have worked. Here is my Australian map.
Clicking on any of the blue grid tiles will show you contacts made into the grid
Some grids are quite rare, not having many amateurs. For example the only contact into QF01 was with Allen, VK3HRA on a SOTA peak. So some SOTA activations are actually putting rare grid squares on air too.
There is also a "3D view" tick box, showing grid "towers" indicating number of contacts into each grid. Tried this out. Looks cool.
Note the "towers" on the main city centres in Australia, Melbourne, Sydney, Newcastle area and Brisbane.
The tower in the centre of Australia is where log entries for VK contacts with no grid square end up. Quite a lot of amateurs leave this detail off QRZ.com, so unable to fill it in.
You really appreciate from the map how large Australia is, and sparsely populated it is in the desert centre. Even close by Western NSW and Western Victoria have empty grids! To work all VK grids would be impossible.
Having seen I have worked lots of grid squares, went looking for an award for claiming them. Found the Wireless Institute of Australia (WIA) website has an online award for working 100 grids. Fed in my log in Adif format to see if I qualified.
27 Grids confirmed on SSB, with 261 on Digital (JT65), giving 278 grids confirmed, and able to claim the award! Applied, to wait for endorsement to claim it.
Update, Awards endorsed and arrived! Look good : )
WIA Award for confirming 100 Grid Squares Open
And award for confirming 100 Grid Squares Digital (in my case JT65 mode)