Yaarel
🇮🇱He-Mage
No it's not. Look up what publishing means.
If I post a homebrew race here in a thread, nothing has been published.
Here is from West's Encyclopedia of American Law (2008).
Publish
To circulate, distribute, or print information for the public at large.
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The meaning of the term publish differs according to the context in which it is used. In its broadest sense, the term publishing describes the act of making something known to the general public. A publication can be accomplished by speaking in a public place, printing information on paper and distributing it on the street, buying or otherwise securing time on television, placing information in a circulated newspaper or magazine, or other similar methods.
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Posting on ENWorld is "publishing".