This post is part of a Joomla article package that I hope will be informative to those who are new to Joomla which hopefully Joomla experts can help enhance. Open Source software and commercial software are different in various aspects. Cost being the primary differentiator may play a vital role in your choice of a CMS. Open source CMS comes at no or marginal cost while Commercial Software are relatively higher priced. It is generally believed that the commercial CMS provide better post-installation assistance in documentation, training, stability, security issues etc. as their support staff may be available when needed. This may not be possible in open source CMS which primarily runs on the support of volunteers and not regular staff. However, Joomla! is a pleasant exception!. With thousands of developers on the project, it has built a reputation for its prompt and effective customer service. Moreover, with a strong volunteer-base, Joomla! can boast of continual development resulting in timely upgrades and new releases. You may look at your specific CMS requirements, business conditions, available resources and client requirements while choosing a CMS. Factors like price; implementation; documentation, training and support services and customization opportunities should not be overlooked. Some of the Free and Open Source CMS include – Joomla!, Mambo, Drupal, PHPNuke, Post Nuke, Plone, TYPO3, e107, Open CMS, MODx CMS, WordPress, XOOPS and Zope. Some of the Commercial Software include – Vignette, Alfresco, RedDot CMS, Interwoven Teamsite, Tridion, Microsoft CMS, Oracle portal, Immediacy CMS, GOSS iCM, Hot Banana and Fatwire Content Server. Comparing Joomla! with other open source CMS Joomla! is comparable to most leading CMS systems in terms of its features. There are some features in Joomla! which Drupal, Plone and TYPO3 only offer as free add-on, examples of such features are job posting, guest book, chat etc. All open source CMS are distributed under GNU GPL and may gel well with any of the operating systems. What sets Joomla! apart from the others is a strong developer community. This reflects in its highly efficient and consistent development program. The following chart tries to compare leading open source CMS based on a few important parameters. As compared to open source CMS like Joomla!, commercial CMS are distributed under commercial or proprietary licenses. They may use diverse databases but Oracle and Microsoft SQL server are common. Also the programming language they use varies a lot. This includes PHP, Java, Java Script, .NET, XML, XSL, JSP, Perl, etc. Unlike open source CMS like Joomla!, commercial CMS may require specific operating systems for implementation. Vignette prefers Windows XP/2000/2003 while Oracle supports Windows, UNIX and LINUX. Like Joomla!, the web servers Apache and IIS are common in commercial CMS also. Other than these technical specifications, there are many other factors for comparison. Features, built-in applications, support, commerce, flexibility, interoperability, management, performance, ease of use, security, etc are just some of them. Joomla! scores high on all of those parameters. Its growing popularity just underlines this fact.