The actual license from a current OmniFocus disk image reads:
So, you can run it on multiple machines so that you can sync between them, but no one else is allowed to use it, if you have a single license.
The license permits either (a) multiple users to install and use the Software on a single machine; or (b) a single user to install and use the Software on multiple machines. However, a single license does not allow multiple users to ever use Software on multiple machines, regardless of whether such use is concurrent, except in the case of Family Pack licensing.
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