Is licensing your contributions to stack exchange under CC0 legal?
<p>Some users have added</p>
<blockquote>
<p>Everything I post on Stack Overflow is licensed to you under CC0</p>
</blockquote>
<p>to their profiles. I would like to know whether this is legal, because as far as I know stack exchange uses CC4.0, and I am not sure whether or not it is legal to add that to my Profile.</p>

<p>It's not illegal to say things in your profile. SE requires you to license your content to them  on a non-exclusive basis pursuant to CC BY-SA 4.0. &quot;Non-exclusive&quot; means that you can also license the material to others on some other basis, e.g. CC0. In that case, a person who uses your material can rely on the other license that you granted.</p>
<p>If SE wanted to, it could prohibit putting licenses in a user profile, in which case you would have to promulgate your more generous license elsewhere.</p>

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