What's the difference in CRM, ERP, CMS?

CRM is focused on sales and marketing, ERP is focused on administration and management. ERPSy, ERP Easy, the Easy ERP, even more Insight

Customer Relationship Management (CRM)
Manage interaction with current and future customers. Use technology to organize, automate and synchronize sales, marketing, customer service, and technical support

Enterprise Resource Management (ERP)
Store and manage data from stages of the business cycle. Product planning, cost and development, Manufacturing, Marketing and sales, Inventory management, Shipping and payment

Content Management System (CMS)
Publish, edit and modify content and maintenance from a content interface. Avoids continuous computer programming.