vBulletin 3 (I am not paying for that shit, let Slavski do it)
vBulletin (abbreviated as vB) is a commercial Internet forum package produced by Jelsoft Enterprises Ltd. Written in PHP using a MySQL database server, it is comparable to other forum software.
In 1999 James Limm and John Percival were running a Visual Basic website using Infopop's UBB.classic forum software on VB Forums. As their site grew, they noticed that their software, written in Perl using a flat-file database, could not always cope with the number of users they had. In February 2000, the two decided that it would be better to write their own solution as both were unfamiliar with the software's code and thus unable to optimize it. Initially, it was designed solely as a rewrite of UBB, but in PHP using MySQL, and was meant only for their forum. However, a few months later, other UBB owners expressed interest in the solution. Because of this, they offered to sell it to Infopop, but their proposal was rejected. As there was still a demand for the software, Limm and Percival created Jelsoft and released their work as a paid solution, thus becoming vBulletin 1.
After subsequent minor releases of their software, the two decided to start working on a new version that would be more than a rewrite of UBB: they wanted to turn their software into a competitive solution for forums. Rewriting the entirety of the product, vBulletin 2 commenced development. Shortly thereafter, Limm became the managing director and Percival the lead developer. To help with the scale of the project, two additional developers, Freddie Bingham and Mike Sullivan were brought on to help finish vBulletin 2. Kier Darby was brought on during the vBulletin 2.0 Beta phase to further development. The release of vBulletin 2 proved to be very successful and is what made vBulletin popular.
In December 2002, vBulletin 3 was beginning development. Percival decided to step down as lead developer and product manager, turning his roles over to Kier Darby. vBulletin 3 was under development for a lengthy period of time—nearly 2 years—as it went from a mere improvement on vBulletin 2 to a complete rewrite. However, version 3 was finally released in March 2004. In 2005, vBulletin 3.5 was released that addressed some of the shortcomings of 3.0 (discussed later on). vBulletin 3.6 was released as a stable version on August 3, 2006.
www.vbulletin.com/Since the initial release of vBulletin in 2000, there have been many improvements of the software. The current stable version of vBulletin is 3.6.8.
Below is a list of the major revisions and what they improved on from the previous version.
[edit] v3.6
vBulletin 3.6 adds a number of major features over version 3.5. vBulletin 3.6.0 is available for customers to download via the Members Area. The latest version supports many new features previously requested. So far the major features that have been added are Multi-Quote, Infraction System, RSS Poster Robot and Podcasting Support. Also a large number of smaller features were added. For details (and a full list + screenshots) please refer to the original thread at vBulletin.com. The Gold version of vBulletin 3.6.0 was released on August 3, 2006 [3].
[edit] Latest release
The latest supported release of vBulletin is 3.6.7 PL1 which was released on May 15, 2007. This version contains all the bug fixes that were omitted from 3.6.6 including an xss vulnerability and includes several changes and improvements, most notably full support for the upcoming Project Tools and Blog products and several new hook locations.
[edit] v3.5
vBulletin 3.5 addressed some of the shortcomings of version 3.0. Here are a few of the changes:
* A plugin system that allows for modifications of the software without the need to edit the program scripts. This allows a forum operator to keep their modifications (called "hacks" in the vBulletin community) and not having to re-edit scripts after upgrading.
* AJAX (Asynchronous Javascript and XML) editing of thread titles and post content.
* Inline moderation, allowing forum operators to manage threads and posts on their board without having to go through intermediary steps.
* An API system (referred to as "data managers") to let third-parties integrate more easily.
* Template history and comparison where administrators can store a specific revision of a template into the database, which can be arbitrarily compared against each another.
* MySQLi wrapper that adds support for MySQL 4.1.
* A database-stored thread marking system. Previous versions of vBulletin relied on a variable stored in the database, and also a cookie, to store information about what threads had been read and not read by the user. However, this information was volatile and did not keep; plus if you merely idled for 15 minutes (some forums have longer timeouts, 15 minutes is the default) this information would be lost.
[edit] v3.0
Initially, version 3.0 was intended to be an extension of the 2.x release that would improve performance and user experience. However, as time progressed, it proved to be a complete rewrite. Some of the key advantages over vBulletin 2 are:
* The templates and style use XHTML and CSS.
* None of the language displayed by vBulletin is hard-coded in English; there's support for multiple languages by use of phrases.
* A WYSIWYG editor for users to post in.
* Paid subscriptions that allow administrators to charge for certain features of their site.
* Multiple views for threads: linear (a flat system), threaded (display of the entire thread tree), and hybrid (a combination of both).
[edit] v2.x
vBulletin 2 is no longer under active development, except for security updates. When this version was released, it had numerous new features over vBulletin 1, which it replaced:
* Private messaging to allow users to communicate in private.
* Polls could be attached to threads.
* Nested forums of unlimited depth. This allowed forums to be children of each other without constraints.
* User avatars.
* A user control panel that allows users to control various board options.
[edit] v1.x and vBulletin Lite
Development of vBulletin 1 is no longer active; also, it is no longer a supported release.
vBulletin 1 was the initial release of vBulletin, sporting the same features as UBB.classic. The release was very popular as it was one of the first systems that was written using PHP and MySQL that had the features of UBB.
vBulletin Lite was a degraded version of the 1.x series that allowed potential customers to test their server for compatibility with vBulletin. The product was discontinued after vBulletin 2 because there were security issues and it was out of date, and Jelsoft did not want to spend resources into maintaining a non-commercial product.
But I'm not an expert. 
