Salesforce.com
Salesforce.com was the early leader in the Software as a Service arena back in 1999. The founders felt traditional software development would eventually be replaced with web based services.
Salesforce.com’s flagship product is a web-based CRM (Customer Relationship Management) solution. As of September 2007, they had over 900,000 subscribers and supported 100-million customer transactions in one day.
In 2007 Salesforce.com launched Force.com, a Platform-As-A-Service, as the a building block platform for additional web based software services.