If you have a website that is integrated with your WordPress blog, be cautious when upgrading to WordPress 3.0. It will break your website in a very devious way, potentially causing massive damage to your SEO efforts! But now that you know the danger, just keep reading and see how easy it is to avoid the pitfall.
Before WordPress 3.0, integrating your WordPress blog into your website meant following the instructions at WordPress.org to include a wp-blog-header.php require statement and some other goodies to make the connection. This method no longer works with WordPress 3.0.
But you won’t know at first glance that anything is wrong! Your website will load just fine. Your blog posts will display correctly. You’ll soon discover a terrible problem though. Your first indication of any issue may come a week later in an email from Google telling you that your Adwords campaign has been suspended because of 404 errors. Or Google will mysteriously start reporting 404 crawl errors. And this is what makes it such a heinous bug, because even though its obvious your website is loading just fine, it’s erroneously being reported as a 404! Potentially destroying all of your SEO efforts.
The fix. Instead of using:require('./wp-blog-header.php'); use,
require('./wp-load.php');
Suddenly all your problems will disappear. Huge problem. Easy fix. Whew!
(A quick way to test the status response of your web page is to visit http://www.seoconsultants.com/tools/headers and enter your url.)
The tip saved me some frustration with erroneous 404 headers on pages that were scraping post content with a modified version of the WordPress loop. Thanks a bundle.