As a developer, I’ve been involved with Salesforce for about six years and found the marketing around Force.com, Salesforce.com and Salesforce1 to be really confusing. I hope that this post will clear up some of your misconceptions and help you to understand what the differences are.
Force.com is the platform that the Salesforce CRM and your customizations run on. The Force.com platform consists of a multi-tenant architecture that runs on application services, web servers and of course database servers. Salesforce is using Java, and Oracle for significant parts of the Force.com Platform.
Force.com is also a platform as a service (PaaS) that can be purchased separately and won’t include a lot of the key CRM functionality like Leads, and Opportunities. Lately, Salesforce has started to advertise an additional cloud called the “AppCloud” which includes services like Heroku which is another server that Salesforce owns.
Salesforce.com is generally used to refer to the CRM functionality only, so this would be the “sales cloud”, “service cloud”, and marketing related clouds. Salesforce is running on the Force.com Platform.
Salesforce1 is the mobile application that Salesforce has developed which is available on Android and iOS. It’s possible for developers to add functionality which can be used in the mobile phone application.