The founders of AppRiver had a powerful solution for identifying and filtering spam and virus-laden e-mail messages for business customers. But they wanted to be in the business of managing and delivering their service, not managing and maintaining the servers supporting the service. They knew that Rackspace could provide the core services they needed to support their business model—and that by outsourcing their hosting to Rackspace they could focus on building their business and supporting their customers. More than two and a half years later, AppRiver's focus has not shifted: It has built its business to the point where it filters as many as one billion mail messages per day for more than 40,000 customers around the world—and it relies on Rackspace to manage the more than 500 servers that keep its antispam and antivirus filters running around the clock.

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