My Stamps are the stamps you unlock by achieving hidden tasks, purchasing from the Stamp Store or being gifted by your friends. You can use the stamps inside this album in your own letter for unlimited times.
Stamp Collection includes all stamps in your My Stamp album, plus the stamps you received from your friend's letters. This album is like a stamp collecting album for viewing only. The concept is similar to our real life experience that you cannot re-use a stamp from a received letter, but you can take the stamp off from the envelope and put it into your stamp album for collection.