There are actually quite a few places where you can put profiles on a Mac.
You can have profiles available to everyone on the computer, or limit them to just yourself. Also, putting them in a different location would order them differently in the list of profiles in Photoshop (for example.)
If you want the profiles available to any user on your computer, the folder you mentioned is a good place. (Just putting them here is fine.) :
HD > Library > ColorSync > Profiles
If you want them limited to only one user, put them here:
HD > Users > “username” > Library > ColorSync > Profiles
Any folders “deeper” into these locations will not be recognized by ColorSync, Adobe or ColorThink. In fact, ColorThink creates a “Disabled Profiles” folder (using the Profile Manager) in which profiles are moved that you don’t want to see. The “Recommended” folder is a good example of this.
There are other application-specific places where profiles are located. There are also some pretty obscure places where your printer driver installation puts more profiles.