Trainer spy programs are a love-hate relationship, or simply hate, for many game hackers. If you do not know what a trainer spy does, it tells you where a trainer writes data to a game (with other information).
That information is useful as you know what process a trainer writes to (many games have several processes), the address it writes to, the size of written data in bytes, and what is written.
The intended purpose of what to do with that information varies by users, stealing trainer details to make their "own" trainer, learning purposes, or by the trainer author to verify their trainer works correctly.
*Updated 01/11/2012
