"All aspects of the platform are open to you, so you can build apps on top of the platform," Marc Benioff, Salesforce.com's CEO, told the attendees at Dreamforce, the company's main user and developer conference. "You don't have to create your own infrastructure. Those days are over."

Businesses who sign up for the service will have many enterprise application choices. Since it launched, the Force.com platform has harbored nearly 85,000 customers. Some build upon core enterprise apps such as Salesforce.com's CRM system, while others deal with other business departments, such as HR, IT and marketing.

The announcement comes at a time when SaaS, a model of software delivery where vendors like Salesforce.com host data while employees at companies access the application through a Web-browser, is being looked upon more closely by more businesses due to the recession.

SaaS works on a pay-as-go model (generally per user per month), a departure from multi-year, multi-million dollar software contracts of the past where companies generally had to buy servers and host the data themselves.

While Salesforce.com has taken a beating on Wall Street, watching its stock price fall 18 percent in a 24 hour period back in August , the company has done $1 billion in revenue this year.

Salesforce.com has generally been focused on internally facing applications. With the announcement of Sites, they are expanding their presence in a market crowded with service providers big and small. Benioff, in his remarks, seemed to acknowledge this fact.

"It's time for you to think of us in a different way," he says. "We're going to do it with Force.com Sites. Now you can run your whole web in our cloud. You can run all your web applications on force.com. Not just your CRM."

The service, set to hit in 2009, will vary its pricing model based on the amount of page views a website experiences. Developers can get a preview of it at force.com.