I have mac-book and i-mac, then need 2 copies omni focus ?

What's mean '1 seat license' ?
thank you.

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'one person license' posted at http://www.omnigroup.com/applications/omnifocus/

but '1 seat license' at invoice receipt . ? ? ?
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I'm solve this question after reading /store.omnigroup.com/licensing

[sfkeydel]

I believe it's a "one-person" license, rather than "one-seat." Regardless, I'm sure that you may use it on more than one computer, provided you are limiting its use to yourself.

Interestingly, the "Support" link on the main product page is focused almost exclusively on OmniFocus for iPhone issues, so one could be forgiven for being confused about this.