Memory Repossessed shows the amount of memory reclaimed by ESX.
Balloon
Amount of memory reclaimed by ESX via ballooning to give to other virtual machines.
Note: For memory to be reclaimed via ballooning, VMware Tools must be installed on the virtual machine.
ESX Swapped
Amount of memory reclaimed by ESX via swapping to give to other virtual machines.
Memory reclaimed via swapping can affect the performance of the virtual machine significantly more than if the memory is reclaimed via ballooning.