ClearOS - A very good alternative for Windows Server, for free
Synthesio - Synthesio is a social intelligence tool or a marketing software that is specially made for the purpose of social media monitoring and social analytics.
NethServer - NethServer is an operating system for Linux enthusiasts, designed for small offices and medium...
Swift Social - All-in-One Social Media Growth and Management Tool
Univention Corporate Server - Univention Corporate Server UCS with Active Directory functions and App Center is the cost-efficient and popular successor to Microsoft's server solutions.
LeadsRX - LeadsRX is a marketing attribution software that gives marketers insights into which advertising campaigns result in conversions.