Salesforce.com Monday released a new high-end take on its on-demand customer relationship management (CRM) software. The vendor is hoping the product, dubbed Unlimited Edition, will encourage its customers to host more of their non-CRM applications on its AppExchange network.

Salesforce.com now offers four editions of its on-demand CRM -- Team, Professional, Enterprise and Unlimited. Unlimited is available now and costs US$195 per user per month.

Unlimited Edition is a further step up from Enterprise Edition, according to George Hu, senior vice president of applications at Salesforce.com. Where Enterprise Edition gave users a maximum storage capability of 20M bytes per user, Unlimited Edition provides 120M bytes of storage per user. "We want storage not to be an issue," Hu said in a recent phone interview.

While Enterprise Edition could support 10 custom applications within AppExchange, Salesforce.com is positioning Unlimited Edition as being able to support as many applications as customers need, according to Hu. AppExchange, which went live in January, is a network designed to host third-party and custom applications and integrate them with Salesforce.com’s CRM software. AppExchange is running 188 hosted applications and components from third parties, Hu said.

Unlimited Edition includes all the features of Enterprise Edition plus Salesforce Sandbox, a secure application environment where customers can create a working replica of applications they intend to deploy so that they can test them out.

Real estate development and public works company EarthCalc uses Salesforce.com to run its entire business, according to Carlos Basulto, the company’s vice president of information systems, IT and operations.

"The Unlimited Edition features are precisely what we need to maximize our utilization of Salesforce.com," he wrote in an e-mail request for comment. "The storage capacity of Unlimited Edition was a factor in our decision to upgrade." EarthCalc has already purchased Unlimited Edition, he added. The company became a Salesforce.com customer in October 2005 and has 16 users of the software.

Currently, EarthCalc has four AppExchange applications running -- budgeting and purchase order management, e-mail marketing campaigns, project management and employee records management, according to Basulto. The company intends to add more applications soon.

In recent months, Salesforce.com has attracted plenty of criticism for a number of outages of its service and how it communicated with customers over those service losses. "We did have some hiccups," Hu said.

Salesforce.com has responded to the negative feedback by embarking on a major overhaul of its IT infrastructure to the tune of US$50 million. Last month, the vendor also established a Web site aimed at providing customers with real-time information about status of its systems and likely upcoming operational issues including maintenance.