6 digit refers to how long the STEAMID of the account is.

This is a steam id:

STEAM_0:0:123456

123456 = The account id (the 6 he is refering to, ranges from a few digits to alot)

_0 = The universe it belongs to, 0 means individual

:0: = The type 0 = unspecified (old accounts), 1 = individual

Thats the break down, your steamid is used in game, if you get banned from a server by STEAMID, you can only be unbanned by the server admins. If you get banned by IP you can rejoin when your IP changes, by name you just change it and rejoin. A STEAMID never changes, you get VAC banned, you can never play on your account again on VAC servers. All games added to an account cannot be moved or removed. Once you enter the product key into steam, or buy one directly, its tied to that account.

// im done, just some STEAMID info. (im a css gamer/server admin)