When it comes to Web development, there is a wealth of free information online to help you create a top-notch Web site. A lot of hard work goes in to maintaining these resources, all to help save you time and money. The Open Source community is growing stronger everyday and the scripts are getting more useful and efficient, making it almost impossible to not use a few of them in your project. Here is a list of 31 open source Web development scripts I have either used or read about that would easily help any developer with their next project.

Ad Servers

Open X Ad Server

adserver
OpenX is the world’s leading independent ad server. It provides you with the simple tools you need to make money from advertising, whether from direct ad sales, OpenX Market, or third party ad networks (like AdSense).
http://www.openx.org/ad-server

Revsense

revsense
RevSense Ad Server makes it easy for you to sell ads on your site. Set the prices you want, and the kinds of ads to sell, then RevSense does the rest. It manages the sign up, ad entry and upload process and collects advertising revenue into your Paypal or Authorize.net account.
http://www.revsense.com/

Blogging Software

WordPress

wordpress
WordPress is a state-of-the-art publishing platform with a focus on aesthetics, web standards, and usability. WordPress is both free and priceless at the same time. More simply, WordPress is what you use when you want to work with your blogging software, not fight it.
http://wordpress.org

Movable Type

movable
Powerful enough for building blogs, websites or social networks on a single platform. It’s easier than ever to publish and share information with Movable Type. Movable Type makes it simple to start a blog, manage entire websites and build an engaged community of readers and customers.
http://www.movabletype.com

b2evolution

b2evolution
b2evolution is a powerful blog tool you can install on your own website. It includes all the features of traditional blog tools, and extends them with evolved features such as file & photo management, advanced skinning, multiple blogs support as well as detailed user permissions… Not to mention third party plug-ins!
http://b2evolution.net/

Nucleus

nucleus
Nucleus offers you the building blocks you need to create a web presence. Whether you want to create a personal blog, a family page, or an online business site, Nucleus CMS can help you achieve your goals.
http://nucleuscms.org/

Textpattern

textpattern
Textpattern is a flexible, elegant and easy-to-use content management system. It is both free and open source.
http://textpattern.com/

Content Management

Drupal

drupal
Equipped with a powerful blend of features, Drupal supports a variety of websites ranging from personal weblogs to large community-driven websites.
http://drupal.org/

Pligg

pligg
Pligg is an open source Content Management System (CMS) that you can download and use for free. Pligg CMS provides social networking software that encourages visitors to register on your website so that they can submit content and connect with other users.
http://www.pligg.com/

Joomla

joomla
Joomla is an award-winning content management system (CMS), which enables you to build Web sites and powerful online applications. Many aspects, including its ease-of-use and extensibility, have made Joomla the most popular Web site software available.
http://www.joomla.org

Mambo

mambo
Mambo is a full-featured, award-winning content management system that can be used for everything from simple websites to complex corporate applications. It is used all over the world to power government portals, corporate intranets and extranets, ecommerce sites, nonprofit outreach, schools, church, and community sites.
http://mambo-foundation.org/

Customer Service

Help Center Live

helpcenter
Help Center Live is an open-source, community driven live chat & support system. You may easily provide live support on your website just like large companies do with very little work. With Help Center Live, you can provide a real-time, live support or sales person experience.
http://www.helpcenterlive.com/

osTicket

osticket
osTicket is a widely-used open source support ticket system. It seamlessly integrates inquiries created via email, phone and web-based forms into a simple easy-to-use multi-user web interface.
http://www.osticket.com

Crafty Syntax

craftysyntax
Crafty Syntax Live Help (CSLH) is an open source live support solution that helps customer support with live help functionality that can be proactively pushed to visitors to your site or requested by the consumer.
http://www.craftysyntax.com/

eCommerce

osCommerce

oscommerce
osCommerce Online Merchant is an Open Source 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 online stores with minimum effort and with no costs, fees, or limitations involved.
http://www.oscommerce.com/

Magento

magento
Magento is the eCommerce software platform for growth that promises to revolutionize the industry. Its modular architecture and unprecedented flexibility means your business is no longer constrained by your eCommerce platform. Magento is total control.
http://www.magentocommerce.com/

Zen Cart

zencart
Zen Cart truly is the art of e-commerce; free, user-friendly, open source shopping cart software. The ecommerce web site design program is being developed by a group of like-minded shop owners, programmers, designers, and consultants that think ecommerce web design could be and should be done differently.
http://www.zen-cart.com/

Open Cart

opencart
OpenCart is an open source PHP-based online shopping cart system. A robust e-commerce solution for Internet merchants with the ability to create their own online business and participate in e-commerce at a minimal cost.
http://www.opencart.com/

Agora Cart

agora
AgoraCart – The powerful “Free” Open Source ecommerce shopping cart software solution offers you a very wide range of features that allow you to setup an online storefront or shop ranging from a simple template based store for novices to the integration of complex web design concepts created by your web designer.
http://www.agoracart.com/

Education

Moodle

moodleMoodle is a Course Management System (CMS), also known as a Learning Management System (LMS) or a Virtual Learning Environment (VLE). It is a Free web application that educators can use to create effective online learning sites.
http://moodle.org/

Forums

phpBB

phpbb
Since its creation in 2000, phpBB has become the most widely used Open Source forum solution. Like its predecessors, phpBB 3.0 Olympus has an easy to use administration panel and a user friendly installation process, which allows you to have a forum set up in minutes.
http://www.phpbb.com/

BBPress

bbpress
bbPress is forum software with a twist from the creators of WordPress. bbPress is focused on web standards, ease of use, ease of integration, and speed. Were keeping things as small and light as possible while still allowing for great add on features through our extensive plugin system.
http://bbpress.org/

PunBB

punbb
PunBB is a fast and lightweight PHP-powered discussion board. It is released under the GNU General Public License. Its primary goals are to be faster, smaller and less graphically intensive as compared to other discussion boards.
http://punbb.informer.com/

Simple Machines

simplemachines
Simple Machines Forum SMF in short is a free, professional grade software package that allows you to set up your own online community within minutes.
http://www.simplemachines.org/

Mailing Lists

phpList

phplistphplist is an open-source newsletter manager. phplist is free to download, install and use, and is easy to integrate with any website.
http://www.phplist.com/

Dada Mail

dadamail
Dada Mail is a completely contemporary, mature and intuitive web-based e-mail list management system, which runs on most any Unix-like hosting account that can run custom CGI scripts.
http://dadamailproject.com/

poMMo

pommo
poMMo is versatile mass mailing software. It can be used to add a mailing list to your Web site or to organize stand alone mailings. Unique Features such as the ability to mail subsets of your subscribers set it apart from alternatives.
http://pommo.org/

Photo Galleries

Zen Photo

zenphotoZenphoto is an answer to lots of calls for an online gallery solution that just makes sense. After years of bloated software that does everything and your dishes, zenphoto just shows your photos, simply. Its got all the functionality and features you need, and nothing you dont.
http://www.zenphoto.org/

Gallery

gallery
Gallery gives you an intuitive way to blend photo management seamlessly into your own website whether you’re running a small personal site or a large community site.
http://gallery.menalto.com/

Pixelpost

pixelpost
Pixelpost is an open-source, standards-compliant, multi-lingual, fully extensible photoblog application for the web.
http://www.pixelpost.org/

Piwigo

piwigo
Piwigo is a photo gallery software for the web, built by an active community of users and developers. Extensions make Piwigo easily customizable. Icing on the cake, Piwigo is free and opensource.
http://piwigo.org/