"That's why we've made huge investments in all this new technology," he said. "We've wholesale replaced our architecture, our hardware, our software, to get us to the next level [of service]."

However, for one disgruntled user, who asked that he and his company not be identified, the upgrade won't make a difference. The user, who heads a high-tech firm, started using Salesforce.com's CRM service last year. By August, he said, system availability had become intermittent.

The problems induced the company to craft a homegrown CRM application in October. The user said he is encouraged by the Mirrorforce initiative, but he's not going to return to Salesforce.com. "We got benefit from [using Salesforce.com]," he said. "I hope they do well."

Salesforce.com said the upgrade is unrelated to the December outage of its hosted CRM service, which it called a temporary glitch. The outage lasted a full day for some customers, and some critics said it was an indication that the Salesforce.com infrastructure had reached its limit.

-- Elizabeth Montalbano of the IDG News service contributed to this story.