If you join a Homegroup from a Windows 8 machine, you are prompted for a password. This password is subsequently visible whenever you enter the homegroup settings:
This is silly. Is there a way to obscure it?
At current, No.
The prevailing logic for Homegroups is that it's a Leaderless system, meaning that all members have all applicable rights over shared resources (unless specifically defined by the file/directory's original owner).
Since the Homegroup password is considered owned by no one (there is no Homegroup Administrators group like there is on a Domain) then all members of the Homegroup have full access to that information and the password is reference-able at any time un-obscured.
Maybe in the future, as Homegroups become more and more adopted in the general public, more robust securities will be implemented. But as it stands now, that password is considered public knowledge for all members of a Homegroup.