Despite using this plugin with carefully crafted meta titles no wider than 469 pixels (yes its pixels now - NOT 70 characters), and carefully written meta descriptions; Google-bots aggressive use of dates has resulted in our home page being displayed with the 'first published date' showing at the start of or homepage meta description.
Does this affect your rankings?
YOU BET IT DOES!
Like: dropped from #7 on the first page of Google search results, to #25 (3rd page of search results).
This is an ecommerce site and the first published date IS NOT RELEVANT to the content on this page.
Followed the advice on this site: http://www.webmasterworld.com/google/3843934.htm
After 1 month of trying everything else (with virtually zero sales),
this is the ONLY way we were finally successful in stopping Google from showing that ancient 'first published' date at the beginning of our homepage description:
Added last_modified meta date to the header.php (as the first meta tag):
<meta http-equiv="last-modified" content="YYYY-MM-DD@hh:mm:ss TMZ" />
Added last modified date to the homepage.php file:
Updated: <?php the_modified_time('F jS, Y'); ?>
Changed the published time on the actual page (wp-admin) to todays date, and re-published the page.
Resubmitted the xml page sitemap in webmaster tools, did a 'Fetch as Google' in webmaster tools, then submitted URL for re-indexing.
Within 10 minutes our website was back on the first page of Google search results - WITHOUT A DATE BEING SHOWN!