Extended headlines are a great feature which are a must in your adgroups to test against normal ads. When you put any of the below punctuation at the end of desc line 1, it moves next to the headline, this more often than not, increases click through rate, which can lower your cost per click and increase traffic to your site:
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You will see in the video above, the extended headlines only apply to the ads at the top – not the side, the preview shows that as I take the punctuation away, the headline is no longer extended.
Update
Since the introduction of expanded text ads, this practice of using punctuation to extend headlines is no longer required: