This means that you will no longer be contacted by a GM if you have purchased an item. The items for your purchase will be directly transferred to your inventory as a small gift item once we get to check your donation. So check your inventory from time to time (24-48 hours after you donated) for a item like this:
To claim your gift simply right click on the item and select "claim gift":
IF your gift are silver coins, a rod of transmutation, etc. then you are done here. The items should have appeard in your inventory. If you have donated for a wagon for example you will see another popup like this:
Select the wagon you want to have with the drop down menu and click on Claim Gift. Done. There should be a wagon kit in your inventory. This works similar with banners, flags, towers, resource spots, etc... just follow the instructions.