[aparks517]

I don’t expect it to as long as the mark-up is valid. Perhaps someone with more SEO knowledge will stop by to correct me.

[martin_a]

You're right. HTML5 does not work with DTDs anymore, so unclosed tags are not a violation of the document schema and therefore probably not "punishable" by search engines.

[anjbe]

Implicit end tags as described in the article have been allowed by every HTML DTD not named XHTML.