The Apache HTTP Server is a web server for Unix-like systems, Microsoft Windows, Novell NetWare, Mac OS X and other operating systems. Apache is notable for playing a key role in the initial growth of the World Wide Web. As stated by Netcraft, Apache is the most popular web server on the Internet since April 1996.  Read More:httpd.apache.org

Apache has a typical use is in the LAMP web server application stack, yet it can be used in conjunction with Zope, to get the best from both worlds.

Ajax (also known as AJAX), shorthand for Asynchronous JavaScript and XML, is a web development technique for creating interactive web applications. The intent is to make web pages feel more responsive by exchanging small amounts of data with the server behind the scenes, so that the entire web page does not have to be reloaded each time the user requests a change (source: wikipedia).

AJAX techniques are available in Plone mainly through the KSS framework and have a very clean integration with Plone CSS system.

A content management system (CMS) is a system used to organize and facilitate collaborative creation of documents and other content and to manage their publication, without the mediation of technical support structures (source: wikipedia).

eXtreme Programming (XP) is a software methodology and a modern approach to software development. It was meant to increase success in complex or risky project and improve developers productivity. eXtreme programming techniques apply to different development phases such as Programming, Design, Coding, Testing and bring them all together recursively. As peculiar trait, eXtreme programming emphasize customer involvement and promote team work (cit) because of its strong focus on collaboration and interaction between the programmer team and business experts.
Read More: www.extremeprogramming.org

Flash

Adobe Flash, or simply Flash, refers to both the player and to the multimedia authoring program used to create content such as web applications, games and movies, and content for mobile phones and other embedded devices.

In Plone it's easy to include Flash elements: sfw files can be embedded into page templates or added by users as special contents.  Plone extensions can also handle different video formats and multimedia files, including audio files and, of course images.

GPL
The GNU General Public License (GNU GPL or simply GPL) is a widely used free software license, originally written by Richard Stallman for the GNU project. It is the license used by the GNU/Linux operating system and by Plone CMS itself.
Read More: www.gnu.org

The License & Copyright section of the Plone.org website answers some common questions about Plone licensing policy and the GPL.

Javascript
Javascript is a scripting language best known for its use in websites, but is also used to enable scripting access to objects embedded in other applications (source: wikipedia).

Javascript can be associated to Plone products and they are rationally managed through the ZMI: from the portal tools you can add scripts on the fly, control activation, add conditions, merge them and on.

LDAP
LDAP stands for Lightweight Directory Access Protocol, a networking protocol for querying and modifying directory services running over TCP/IP. OpenLDAP is an open source implementation of the LDAP directory services. Active Directory is an implementation of LDAP directory services by Microsoft for use in Windows environments (source: wikipedia).

MySQL is a multithreaded, multi-user SQL database management system (DBMS) which has, according to MySQL AB, more than 10 million installations worldwide. MySQL is popular for web applications and acts as the database component of the so-called LAMP (Linux, Apache, MySQL, PHP / Perl / Python) platforms.
Read More: www.mysql.com

Plone Improvement Proposal (just like python's PEPs: Python Enhancement Proposals). These are documents written by the Plone team to structure and organise proposals for the improvement of Plone.
Read More:www.plone.org

Plone is a free, open source Content Management System. The focus of Plone is to provide value at every level of an organization. It comes with a workflow engine, pre-configured security and roles, a set of content types and multi-lingual support. Plone is mainly written in Python and based on the Zope Content Management Framework.
Read More:www.plone.org

Postgresql
PostgreSQL is a powerful, open source relational database system. It has more than 15 years of active development and a proven architecture that has earned it a strong reputation for reliability, data integrity, and correctness. It runs on all major operating systems, including Linux, UNIX (AIX, BSD, HP-UX, SGI IRIX, Mac OS X, Solaris, Tru64), and Windows. It is fully ACID compliant, has full support for foreign keys, joins, views, triggers, and stored procedures (in multiple languages).
Read More:www.postgresql.org

Python
Python is a dynamic object-oriented programming language that can be used for many kinds of software development.It combines remarkable power with very clear syntax. Python offers strong support for integration with other languages and tools, comes with extensive standard libraries, and can be learned in a few days.>
The Python implementation is higlhly portable and it is released under an OSI approved open source license.
Read More:www.python.org

RSS is a family of web feed formats used to publish frequently updated digital content, such as blogs, news feeds or podcasts.
RSS formats are specified in XML (a generic specification for data formats). RSS delivers its information as an XML file called an "RSS feed," "webfeed," "RSS stream," or "RSS channel" (source: wikipedia).

Plone makes a wide use of  XML / XSLT which gives a high degree of flexibility. Plone content can be exported and, imported in XML. Content aggregation an delivery is tipycally done through RSS that is perfectly integrated with portal  components

Zope is an open source application server for building content managements, intranets, portals, and custom applications. The Zope community consists of hundreds of companies and thousands of developers all over the world, working on building the platform and Zope applications. Zope is written in Python, a highly-productive, object-oriented scripting language.
Read More:www.zope.org

WebDAV stands for Web-based Distributed Authoring and Versioning. The term refers to the set of extensions to the HTTP protocol that allow users to collaboratively edit and manage files on remote web servers (source: wikipedia)
Read More:www.webdav.org

XML, eXtensible Markup Language, is an extensible language allowing to develop structured documents in a easy way. Designed for the Web to overcome the limitations of HTML, but with the possibility of use in different environments.
Developed by the World Wide Web Consortium (W3C), XML is a subset of SGML (Standard Generalized Markup Language), an international standard that defines the rules to write a markup language.
Read More:www.xml.org