logstash - logstash is a tool for managing events and logs.
HackMD - Fast and flexible, real-time collaborative markdown, inspired by Hackpad.
rsyslog - Rsyslog is an enhanced syslogd supporting, among others, MySQL, PostgreSQL, failover log...
Documize - Enterprise-grade wiki and knowledge management platform
Graylog - Graylog is an open source log management platform for collecting, indexing, and analyzing both structured and unstructured data.
ReadTheDocs - Spend your time on writing high quality documentation, not on the tools to make your documentation work.