2014
easyXDM - Cross-domain messaging made easy
by srcmaxPorthole by ternarylabs
by srcmax2010
2009
Official Google Webmaster Central Blog: Handling legitimate cross-domain content duplication
by srcmaxFor some sites, there are legitimate reasons to duplicate content across different websites — for instance, to migrate to a new domain name using a web server that cannot create server-side redirects. To help with issues that arise on such sites, we're announcing our support of the cross-domain rel="canonical" link element.