What exactly is a 'Grooms Cake' and what is the meaning behind it?

My daily ponder.....

THis is what I found on the 'tradition':

Unlike the bride's cake, which is usually white, the groom's cake was originally a single-layer fruitcake that was boxed for guests to take home. (A single woman who slept with it under her pillow would supposedly dream of her future husband.) The expense and lobor ended the tradition.

Nowadays, it's usually baked in the groom's favorite flavor, and often in a shape that reflects one of his hobbies or interests.