Since those customers already use Salesforce.com for business tasks like managing customer relationships, human resources, and customer support, the idea is that by moving your website and other external apps to Force.com Sites, your company can use a single common architecture – in this case, Salesforce.com’s “cloud.” Like other cloud computing offerings, Salesforce.com is charging based on usage, with certain levels of page views included as part of the company’s existing subscription options.
As an example, ThomasNet (a marketplace for industrial products) uses Salesforce.com for managing their recruitment efforts. Now, they’ve moved job applications over to Force.com Sites, and those submissions flow right into the company’s Salesforce.com app. Previously, this would require a Salesforce.com customer to integrate with their existing job site, but now, it can be turned on and managed all through the Web interface that Salesforce provides.