Few would argue that Salesforce.com has made customer relationship management a household name. But the field of CRM competitors is continuing to swell, with software makers and service providers of all sizes challenging the pioneer.Microsoft, NetSuite, Oracle, SAP, Sugar CRM, and Zoho all have CRM offerings --- to name a few of the biggest -- though they run the gamut of cost, scalability and features.CRM tools help organizations track customer interactions in real-time across the organization, including sales and support.Research firm IDC's Worldwide Customer Relationship Management Applications Tracker found that the global market for CRM software increased 12.8% from the first half of 2009 to the same period in 2010. The global market reached $8.5 billion for the first half of 2010, according to IDC.Oracle was at the head of the CRM pack, with 14.5% global share, while SAP and Salesforce.com trailed in second and third places respectively."The CRM applications market is at the center of the evolution occurring in human engagement," noted Mary Wardley, program vice president for Enterprise Applications and CRM Software at IDC, in IDC's press release. "The rise in social media and social networking is changing the nature and format of not only customer to business interactions, but employee to customer, customer to customer, and partner to business." Applications "will experience a radical change over the course of the next five years" because of fast-changing go-to-market strategies of organizations responding to new demands, she added.Rebecca Wetterman, vice president of Nucleus Research, feels similarly crediting the widening CRM pool for the technology's mass appeal. "Some companies might look for something at a lower cost point even if it means less functionality or they might need something that is more integrated with back-office applications," Wettermans says.For instance, she calls open-source community-friendly Zoho, although limited in capabilities, reasonably priced. Alternatively, she points to NetSuite as a company focused on sophisticated functionality with ties into financials and other critical databases.Wetterman believes the CRM battle will rage on, especially with more organizations relying on the cloud. "SaaS vendors consistently add functionality to their offerings because they have to keep proving themselves to subscribers," she says.Users also want increased customization and demand that providers allow them to configure, add and change the application on the fly. Mobility is another key feature they expect, wanting to access data from their smartphones, tablets and other wireless devices.To get to true mobility, though, CRM applications have to be able to receive, centralize, integrate and distribute data to remote workers.While Wetterman does see competition continuing to ramp up, she considers Salesforce.com still a formidable opponent. "As margins get tighter, companies that tried to do homegrown applications are turning to Salesforce.com, proving that global CRM can be a valuable tool," she says.