Steam finally introduced the Steam Families feature that makes it easier to share video games among family members. This feature was announced last March in Beta testing and was activated this morning. Through it six Steam accounts can be placed in one family group. All games purchased by a family member can be played by anyone in the same family group but not simultaneously.
Steam Families family heads can also control what games each member can play, control purchases and even filter content that may be deemed inappropriate. If only one game is purchased, it can only be played by one member at a time.
For multi-player games for example, more than one game unit needs to be purchased. Each member will have a save file for the game as well as personal achievements. Steam Families family members however can only be changed once a year.