Do search engines crawl comments?
In CComment5 when your page loads it doesn't have any comments on it. Comments are loaded few seconds later in response to an ajax request. Because of that when the search bot is on your page it won't see the comments. In 2009 Google proposed a specification that would make ajax applications crawlable. CComment5 implements this specification and the google bot (and other search engines that support the specification) will be able to find the comments on your site.