And their focus over the next few years is to be the cloud computing company for businesses. Had a salesforce VP tell me recently that SF wants to dominate non-CRM software (e.g., electronic medical records in the cloud) while Oracle and SAP are still working on figuring out this whole "cloud" thing.
Large businesses are still just entering the cloud with a lot of their software. Salesforce is the company they think of when thinking cloud. There's a lot of power in that.
One thing? They own Heroku, Desk.com, Work.com, and several other companies.