Free web software

Chyrp
Chyrp is a free and open source blog publishing application, developed by Alex Suraci.

Dreamwidth
Dreamwidth is an online journal service based on the LiveJournal code.

Easyrec
easyrec is an open source Web application that provides personalized recommendations using RESTful Web services to be integrated into Web enabled applications.

LAMP (software bundle)
LAMP is an acronym for a solution stack of free, open source software, referring to the first letters of Linux, Apache HTTP Server, MySQL and PHP, principal components to build a viable general ...

Scuttle (software)
Scuttle is a PHP/MySQL-based open source social bookmarking.

ShiftSpace
ShiftSpace is an open-source metaweb or web annotation application and framework that allows altering web pages with different tools.