<p>It seems that Wikipedia only requires a link back to the article as attribution. That's according to <a href="http://meta.stackexchange.com/questions/79000/would-it-be-ok-to-paste-content-from-wikipedia-into-a-popular-empty-tag-wiki/79002#79002">an answer</a> from one of the questions you posted.</p>

<p>In general, I think it's better to write original content for tags, but if a paragraph from Wikipedia is apt, then including it with the link shouldn't be that big of a deal.</p>

<p>I agree though, that anything more than a link (e.g., a licence agreement, or requiring the <em>entire</em> article, not just a part) would be too much for the tag wiki.</p>