Popular Open Source Software

Freelance projects fall into a separate category of projects in that they target independent developers and are inherently smaller in size. The company/person giving the project, might not require to engage a larger company for the project because of the size of the project or, might be doing it just to cut costs. In either case the likelyhood that the project is based on a popular open source solution is very high. This likelihood is confirmed from the high percentage of OSS applications related freelancing projects available in all the freelancing sites. To better equip oneself to work in the freelancing market it is good to get familiarized with the most popular of the OSS applications that are likely to yield freelancing projects. We have compiled a list of such software.

BLOGS

A blog is a user generated website, made up of usually short, frequently updated posts that are arranged chronologically. The content and purposes of blogs varies--from links and commentary about other web sites, to news about a company/person, to diaries, photos, poetry, mini-essays, project updates, even fiction. Blog posts are like instant messages to the web. Some of the popular blogs are the following -

Apache Roller

It is a Java-based, full-featured, multi-blog, multi-user, open source weblog server. Roller was originally written by Dave Johnson. Apache Roller 3.0 is now available to be downloaded.
http://rollerweblogger.org/project/
http://en.wikipedia.org/wiki/Apache_Roller

b2evolution

It is a multi-lingual, multi-user, multi-blog publishing system written in PHP and backed by a MySQL database. It includes features such as file & photo management, advanced skinning, multiple blogs support as well as detailed user permissions. It is distributed under the GNU General Public License and available as free.
http://b2evolution.net/
http://en.wikipedia.org/wiki/B2evolution

Bblog

It is a powerful, elegant personal web publishing system written in PHP and utilizing a MySQL database. It is used to manage frequently updated Web content, especially Weblogs. It is released as free, open source software distributed under the GNU General Public License.
http://www.bblog.com
http://en.wikipedia.org/wiki/BBlog

GeekLog

It is a weblog powered by PHP and MySQL. It allows you within minutes to set up a fully functioning dynamic website. It acts as a blog engine, CMS or web portal with support for comments, trackbacks, multiple syndication formats, spam protection, etc of a system. It is licensed under the terms of the GNU General Public License.
http://www.geeklog.net
http://en.wikipedia.org/wiki/Geeklog

LifeType

It is an open-source blogging platform with support for multiple blogs and users in a single installation. It is written in PHP and backed by a MySQL database. It is licensed under the GNU General Public License. Each blog can be run in its own language. LifeType is the only one to come with a fully featured anti- spam mechanism, to help combat the dreaded blog spam. Media uploads and file handling, fully customizable search engine, friendly URLs and a thorough, easy to use administration area are the core features of LifeType.
http://www.lifetype.net/
http://en.wikipedia.org/wiki/LifeType

Nucleus CMS

It is an open-source blog management software package written in PHP, with a MySQL backend. It allows for maintaining multiple blogs with multiple authors on the same site. It is a light content management system and can be extended using plugins. Its free to download the latest version and distributed under the GNU General Public License.
http://www.nucleuscms.org/
http://en.wikipedia.org/wiki/Nucleus_CMS

PivotLog

It is a web publishing system, written in PHP, is used to manage frequently-updated web content, such as weblogs and other dynamic sites. It is distributed under the GPL and is available free of charge.
http://pivotlog.net/
http://en.wikipedia.org/wiki/Pivotlog

Word Press

It is a blog publishing system written in PHP, with a MySQL database. It has a thriving user and developer community and is one of the most popular blogging software available. Distributed under the GNU General Public License, is free and priceless at the same time
http://wordpress.org/
http://en.wikipedia.org/wiki/Word_press

Content Management Systems(CMS)

CMS is a computer software system used to assist its users in the process of content management. It facilitates the organization, control, and publication of a large body of documents and other content, such as images and multimedia resources. A CMS often facilitates the collaborative creation of documents. A web content management system is software for web site management. Some of the best known CMS are the following:

Apache Lenya

It is an Open Source Java/XML Content Management System. Features include revision control, site management, scheduling, search capabilities and workflow support.
http://lenya.apache.org/
http://en.wikipedia.org/wiki/Apache_Lenya

Daisy

Daisy is a Java/XML open-source content management system based on the Apache Cocoon content management framework. Today, Daisy is in use at major corporations for intranet knowledge bases, product and/or project documentation, and management of content-rich websites.
http://cocoondev.org/daisy/index.html
http://en.wikipedia.org/wiki/Daisy

DragonFly CMS

It is a powerful, feature-rich, Open Source content management system which was based on PHP-Nuke 6.5. The software is written in PHP and powered by either MySQL or PostgreSQL. Its a free software.
http://dragonflycms.org
http://en.wikipedia.org/wiki/Dragonfly_CMS

Drupal

It is a free modular content management framework, content management system and blogging engine. This software package allows an individual or a community of users to easily publish, manage and organize a wide variety of content on a website. Drupal is written in PHP.
http://drupal.org/
http://en.wikipedia.org/wiki/Drupal

Joomla

It is a free and most powerful, open source content management system written with PHP for publishing content on the world wide web and intranets, using the MySQL database. It includes features such as page caching to improve performance, RSS feeds, printable versions of pages, news flashes, blogs, polls, website searching, and language internationalization. It's licensed under the GPL.
http://www.joomla.org/
http://en.wikipedia.org/wiki/Joomla

Mambo

Mambo Open Source(MOS) is a free, open source content management system for creating and managing websites through a simple web interface. It also has advanced features such as page caching to improve performance on busy sites, advanced templating techniques, and a fairly robust API. It is released under the terms of the GNU General Public License.
http://www.mambo-foundation.org/
http://en.wikipedia.org/wiki/Mambo_%28CMS%29

OpenCMS

It is a Professional level Open Source Website Content Management System. OpenCms helps to create and manage complex websites easily without knowledge of html . It is based on Java and XML technology. It is distributed by Alkacon Software under LGPL license. OpenCms is completely free of licensing costs.
http://www.opencms.org/opencms/en/
http://en.wikipedia.org/wiki/OpenCMS

PHP-Nuke

It is a web based automated news publishing and content management system based on PHP and MySQL. The system is fully controlled using a web-based user interface. The system is released as free software under the GNU General Public License.
http://phpnuke.org/
http://en.wikipedia.org/wiki/PHP-Nuke

PLONE

Plone is a ready-to-run content management system that is built on the powerful and free Zope application server. Plone is easy to set up, extremely flexible, and provides you with a system for managing web content that is ideal for project groups, communities, web sites, extranets and intranets. Plone is a free software released under the GNU General Public License.
http://plone.org
http://en.wikipedia.org/wiki/Plone

XOOPS

XOOPS is an acronym of eXtensible Object Oriented Portal System, easy to use web content management system, written in PHP, for websites. It uses a modular architecture allowing users to customize, update and theme their websites. It is the ideal tool for developing small to large dynamic community websites, intra company portals, corporate portals, weblogs etc. It is released under the terms of the GNU General Public License and is free to use, modify and redistribute.
http://www.xoops.org/
http://en.wikipedia.org/wiki/XOOPS

FORUM

An Internet forum is a facility on the World Wide Web for holding discussions and posting user generated content, or the web application software. Technology, computer games, and politics are popular areas for forum themes. Internet forums are also commonly referred to as web forums, message boards, discussion boards, discussion groups, discussion forums, bulletin boards or simply forums. Most commonly used Forums are listed below:

bbPress

It is an internet forum package written in the PHP programming language and available under the GNU General Public License. It is written by the makers of wordpress and is focused on web standards, ease of use, ease of integration, and speed. The forum software is as small and light as possible while still allowing for great add on features through their extensive plugin systems.
http://bbpress.org/
http://en.wikipedia.org/wiki/BbPress

Beehive Forum

It is a free and open source forum system using PHP scripting language and MySQL database . Beehive differs from other forum software is its frame-based interface, which lists discussion titles on the left and displays their contents on the right.
http://www.beehiveforum.net/
http://en.wikipedia.org/wiki/Beehive_Forum

IceBB

It is a powerful open-source Internet forum solution written in PHP and using the MySQL database system. It is also fully customizable, with full skin and language support, plus a powerful admin control center.
http://icebb.net/
http://en.wikipedia.org/wiki/IceBB

Ikonboard

It is a comprehensive web bulletin board system. It allows you to create a truly unique community on your website. It is a free online forum developed in Perl for use on MySQL, PostgreSQL, Oracle, as well as flat file databases.
http://www.ikonboard.com
http://en.wikipedia.org/wiki/Ikonboard

MercuryBoard

It is a powerful message board system with a mixture of features such as object oriented, powerful admin controls, optimized MySQL interaction, 3D permission systems, easy skinning, ease of use, and ease of customization coupled with expandability, and diverse language services. It is written in PHP with MySQL database.
http://www.mercuryboard.com/
http://en.wikipedia.org/wiki/MercuryBoard

phpBB

It is a popular internet forum package written in PHP. The "phpBB" is an abbreviation of PHP Bulletin Board. Available under the GNU General Public License, is a free software. phpBB is one of the most popular forum software.
http://www.phpbb.com
http://en.wikipedia.org/wiki/PhpBB

PHOTO GALLERY

Gallery 2

It is an open source PHP project enabling simple management and publication of photographs and other digital media through a PHP enabled Apache, IIS or Zeus web server. Photo management includes automatic thumbnails, resizing, rotation, and flipping, among other things. Albums can be organized hierarchically and individually controlled by administrators or privileged users.
http://gallery.menalto.com/
http://en.wikipedia.org/wiki/Gallery2

Coppermine Photo Gallery

It is a photo-gallery web application with multimedia capabilities. It requires PHP, MySQL, and ImageMagick, and works with most web server software such as Apache. It is a free software which you can download and install on your webspace. It is licensed under the GNU General Public License.
http://coppermine-gallery.net
http://en.wikipedia.org/wiki/Coppermine_Photo_Gallery

PhpWeb Gallery

It is a free and open source software used to present photo collections on your web site. It requires a server with php and MySQL and released under GNU General Public License.
http://phpwebgallery.net/

Customer relationship management (CRM)

CRM is a broad term that covers concepts used by companies to manage their relationships with customers, including collecting, storing and analyzing customer information. There are four aspects of CRM,

Active CRM

a centralized database for storing data, which can be used to automate business processes and common tasks.

Operational CRM,

the automation or support of customer processes involving sales or service representatives.

Collaborative CRM,

Direct communication with customers not involving sales or service representatives.

Analytical CRM,

the analysis of customer data for a broad range of purposes.

Crafty Syntax Live Help(CSLH)

CSLH is an open source live support solution that helps customer support with live help functionality that can be pro-actively pushed to visitors to your site or requested by the consumer. It includes a large range of features to allow multiple operators, multiple departments and multiple languages to be used. It is free and is programmed in PHP with MySQL. Other features include the ability to create your own questions, auto inviting visitors, refer tracking, page tracking, multiple chat sessions, sound alert, quick responses, customizable graphics, multiple operators.
http://www.craftysyntax.com/

Help Center Live Support

Help Center Live is a Live Support tool written in PHP, using a MySQL database, that allows visitors on a website to hold a conversation in real time with a representative of the website.
http://sourceforge.net/projects/helpcenterlive/
http://www.helpcenterlive.com

osTicket

It is a widely-used open source support ticket system. Plain and simple, is a lightweight feature packed support ticket tool , written mainly using PHP scripting language. The best part is, it's completely free and easy to set up and use. osTicket seamlessly integrates all tickets created via email and web-based form with a simple web interface.
http://www.osticket.com/

Perl Desk

It is a browser based help desk software and email management solution designed to streamline the operation of managing emails, support tickets and customer communications, with built in tracking and response logging. It is an ideal help desk solution for companies with one or more members of staff or for those who want to organize client communications. Browser based help desk, managing incoming e-mails, web submission forms, graphical reporting, create departments, user login area etc are the key features of Perl Desk.
http://www.perldesk.com/

E-COMMERCE

Electronic Commerce is exactly analogous to a marketplace on the Internet. It consists primarily of the distributing, buying, selling, marketing and servicing of products or services over electronic systems such as the Internet and other computer networks. The information technology industry might see it as an electronic business application aimed at commercial transactions. Some of the most popularly used e-commerce software are listed below:

osCommerce

It is an Open Source based online shop e-commerce solution that is available for free under the GNU General Public License. It features a rich set of out-of-the-box online shopping cart functionality that allows store owners to setup, run, and maintain their online stores with minimum effort and with no costs, fees, or limitations involved. It combines Open Source solutions to provide a free and open e-commerce platform, which includes the powerful PHP and the MySQL database server.
http://www.oscommerce.com/

Cube Cart

It is a free to use e-Commerce software designed for allowing individuals and businesses to sell tangible and digital goods on line. It is not released under the GNU General Public License but has a custom licensing model and restrictions apply. The application can be used for free if the opyright link is maintained in the footer..
http://www.cubecart.com/

Zen Cart

It is truly the art of e-commerce; a free, user-friendly, open source shopping cart system. Multiple customer modes, unlimited category depth, multiple sales and discounts, multiple display modes, multiple add banner controller, multiple payment options etc are just a few from a list of features. It offers a strong, growing, helpful online community.
http://www.zen-cart.com/

GuestBook

A guestbook is a logging system that allows visitors of a website to leave a public comment. The purpose of a website guestbook is to display the kind of visitors the site gets, including the part of the world they reside in, and gain feedback from them. This allows the webmaster to access and improve their site. A guestbook is generally a script, which is usually remotely-hosted and written in a language such as Perl, PHP, Python or ASP. Many free guestbook hosts and scripts exist. Some guest books are mentioned here:

MJ Guest

It's a free professional guestbook which is very much user-friendly, powerful, reliable and Stylish. Some of the key features are Setup Utility, Strong anti-hacker input control, AntiSPAM, multi-Database, Graphic Themes, W3C standard-compliant, periodical Updates, PHP Object Oriented stable code etc.
http://www.mdsjack.bo.it

DBGuestBook

It is a free, simple guestbook script that doesn't require a database. It allows you delete entries and ban IP addresses through an easy-to-use, password protected administration interface. There is also a customizable bad words filter. You can receive an e-mail notification anytime someone signs your guestbook.
http://www.dbscripts.net/guestbook/

Silentum GuestBook

It is an easy-to-set-up guestbook system that uses a text file to hold the entries. So MySQL is not required. It can be up and running in a matter of minutes and integrated easily into any page. Spam-related words which, when detected, prevent the entry from being added. There is also a required 4 digit verification code before posting to throw off almost all bots. The guestbook allows for an unlimited number of entries.
http://hypersilence.net/silentum_guestbook.php