This article on Bulbapedia says that:
Released Pokémon cannot be found again in the wild
Does it mean that
- Only the very same pokemon you just released, with all its stats, learned moves and the nickname it had when you released it won't be found anywhere in the game (wild) so that you won't ever be able to encounter it again and re-capture
- The whole pokemon type will be "blacklisted" from suddenly appearing in the wild to attack you?
I haven't ever released a pokemon when I played, so I don't quite understand what that rule means.