Matt said that he doesn't add meta descriptions to his own blog posts on his own blog.
He said it is better you leave your meta descriptions blank than to have duplicate meta descriptions on your site.
Best case is to have 100% unique meta descriptions on all your pages but if that is not possible, then let Google figure out what to show in the search snippets by leaving your meta descriptions blank.
Here is the video:
It does make sense...
Forum discussion at Google+.
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