Hi VK4PK, there is no real rules or entry requirement. You just need to be active on 6m & 2m WSPR and upload your receptions to the WSPRnet database as normal.
The results are gathered by John VK2IJM and put into a results table which is shared online.
If we had enough interested parties we would probably have some sort of awards system going, but at this stage its just the Leaderboard position status and getting an overall idea of how your station is performing or how lucky some stations are being in the right positions to receive the incoming propagation.