When you capture a new Pokémon for your team in Pokémon X and Pokémon Y, the current active critter will receive experience points.
Perhaps a minor feature in the grand scheme of things, but reports have confirmed a change in the upcoming Pokémon generation. When fighting a wild Pokémon, for example using Pikachu against a wild Caterpie, if the creature is caught, Pikachu will receive experience points.
Do you like or loathe the new addition in the upcoming games?