Guilds is an LP incentive program. Miners can stake LP tokens to gain bonuses to mining rewards and pool those bonuses together with other miners in "guilds".
To stake your LP tokens:
$ coal guild stake [amount]
To unstake
$ coal guild unstake [amount]
To create a guild
$ coal guild new
To invite someone to your guild
$ coal guild invite [address]
To join a guild (invite required)
$ coal guild join [guild_address]
To leave a guild
$ coal guild leave
To get current staking info
$ coal guild get