Salesforce is a cloud-based CRM platform headquartered in San Francisco. It has over 82,000 customers and provides a complete suite of marketing, sales, service, and other features. Salesforce uses a multitenant architecture and offers low-cost subscription plans on a pay-as-you-go model starting at $5 per user per month. It allows high levels of customization through tools like Visualforce, Apex, and the AppExchange marketplace.