Blogs:
 b2evolution Nucleus
 pMachine Free
 WordPress

Portals/CMS:
 Drupal
 Geeklog
 Mambo Open Source
 PHP-Nuke
 phpWCMS
 phpWebSite
 Post-Nuke
 Siteframe
 Typo3
 Xoops

Customer Support:
 Crafty Syntax Live Help
 Help Center Live
 osTicket
 PHP Support Tickets
 Support Logic Helpdesk
 Support Services Manager

Discussion Boards:
 Invision Board
 phpBB2
 SMF

E-Commerce:
 CubeCart
 OS Commerce
 Zen Cart

FAQ:
 FAQMasterFlex

Guestbooks:
 ViPER Guestbook

Image Galleries:
 4images Gallery
 Coppermine Photo Gallery
 Gallery

Mailing List:
 PHPlist

Polls and Surveys:
 Advanced Poll
 phpESP
 PHPSurveyor

Project Management:
 PHProjekt
 dotProject

Site Builder:
 Soholaunch Pro Edition

Wiki:
 PhpWiki
 TikiWiki

Other Scripts:
 Dew-NewPHPLinks
 Moodle
 Noah's Classifieds
 Open-Realty
 phpAdsNew
 PHPauction
 phpCOIN
 phpFormGenerator
 WebCalendar