Zimbra - Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
uberflip - Organize and Centralize ALL of your Content in minutes
iRedMail - A fully fledged, free email server solution, an open source project (GPL v2).
CoSchedule - CoSchedule is the #1 marketing calendar that helps you stay organized and get sh*t done. Plan, produce, publish and promote your content.
mailcow - An open source mailserver suite.
Embedly - Embedly helps publishers and consumers manage embed codes from websites and APIs.