These keyboard equivalents are reserved across all applications. If your application does not support one of these commands, it should not use these keys for any other function. This restriction is for the user╒s benefit; it gives them guaranteed, predictable behavior across all applications. Using Command-O to mean ╥Open...╙ ninety-nine percent of the time and ╥Ostracize...╙ in your special case does two things: 1) users do not consider using Command-O, as it is already taken by all other applications, and 2) the variability of the equivalent only weakens their perception of consistency.
Other Common Keyboard Equivalents
F Find╔ T Plain Text
G Find Again B Bold
I Italic
U Underline
These Command keys equivalents are secondary to the standard keys previously listed. If your product does not support one of these functions, then feel free to use these equivalents as you wish.
Note that the keyboard equivalents for Print╔ and Plain Text are different from past Human Interface guidelines, which suggested P for Plain Text and nothing at all for Print. The marketplace has, by and large, standardized upon P for Print, leaving no common Command key equivalent for Plain Text. Apple has accepted this change and now suggests standardizing on T for Plain Text, based upon its mnemonic value and common usage among applications that use P for Print.
Unnecessary Command Keys
There should not be Command key equivalents for infrequently used menu commands. This type of usage only burdens your users and constrains your life even more. Only add Command key equivalents to commands your users use most frequently. As infrequently as it is chosen by most users, ╥Page Setup╔╙ is an example of menu command that does not need a key equivalent.
