HubSpot

HubSpot is a CRM ("customer relationship management") system, used not only to build and manage the customer base, but also providing a number of tools for sales support and organization, social media marketing, content management and task planning. It offers integration with salesforce.com, SugarCRM, NetSuite, Microsoft Dynamics CRM and others. It has a large collection of well-documented tools and APIs that allow for full integration with the company's ecosystem.