As you know, Agency Fusion offers a content management system (CMS), that resellers can brand as their own and resell to their clients for a profit.
When resellers ask us for tips on persuading more clients to purchase a CMS, we're usually quick to mention the benefits of having fresh content on a site. Our friends at SEO.com have a nice write-up, including some good visuals, that help illustrate just how important fresh content is from an SEO standpoint.
Here's a graph from the article showing a drop in organic search traffic as a result of letting content go stale for 4 months:
Check out the full article here.