Customer Relationship Management (CRM) involves managing all aspects of a customer's relationship with a company. It uses technologies like data warehousing, data mining, and online analytical processing to collect and analyze customer data to better understand customer needs and interactions. This allows companies to increase customer retention and find new customers. Major CRM software vendors include Siebel, SAP, Oracle, and Microsoft. While CRM can improve customer service and sales, it also requires significant resources to implement properly.