In console you can type "amx_names <playername>" and you will have a list of the ten most common names ever used by that player.
The names are ordered by frequency and last time of use.
When someone enters the server a welcome msg is displayed to all clients (or admins only depending on compile).
If someone enters with a name less common than previously used names for that player,
the welcome msg will also contain up to three names most commonly used by the player.
Example: If I play 20 maps with the name "JGHG" and then 10 maps with "Johnny got his gun", and I enter another map
with the name "Faken Icker" the welcome msg should look like "We welcome Faken Icker, aka: JGHG, Johnny got his gun".