Skype uses P2P (peer-to-peer) technology to provide voice- and video-based communication with other Internet users. The technology is extremely advanced, but easy to use. It features excellent sound quality, end-to-end encryption, and automatic negotiation of firewalls or routers. Among major features are SkypeOut and SkypeIn, adding the possibility to make low-cost calls to land line phones and having a fixed number to be able to receive calls from land line phones.
x11vnc allows one to remotely view and interact with real X displays (i.e. a display corresponding to a physical monitor, keyboard, and mouse) with any VNC viewer. It is designed to be compatible with all Unix variants and Mac OS X, and depends on a small set of standard libraries. It supports SSL/TLS and VeNCrypt encryption, Unix password logins, single port access, Zeroconf, file transfer, and UltraVNC extensions. It is part of the LibVNCServer project.
Moodle is a learning management system for producing Internet-based course Web sites. It is written in PHP and is easy to install and use on Linux, Windows, Mac OS X, SunOS, BSD, and Netware 6. It has been designed to support modern pedagogies based on social constructionist theory, and includes activity modules such as forums, chats, resources, journals, quizzes, surveys, choices, workshops, glossaries, lessons, and assignments. It has been translated into over 70 languages, with more on the way, and supports the popular SCORM standard for content packaging. Moodle offers a free alternative to commercial software such as WebCT or Blackboard, and is being used by a growing number of universities, schools, and independent teachers for distance education or to supplement face-to-face teaching.
SaluSafe is an encrypted email, chat, and file storage and sharing system. Your email and files are highly encrypted end-to-end, and cannot be intercepted by any third party. It was built from the ground up for security via strong cryptography, and is not just another security wrapper on top of an existing email solution.
PhpWiki is a WikiWikiWeb clone written in PHP. A Wiki is a Web site where anyone can edit or create the pages through the Web browser, with no authentication. PhpWiki works right out of the box with zero configuration, and comes with a set of default pages. It's useful for collaborating on documentation on a project, having freeform discussions, and easy editing and searching.
KVirc is a Visual Internet Relay Chat Client based on the Qt library. Features include a MDI user interface, drag & drop, built-in scripting language (aliases, popups and events), customizable backgrounds and colours, DCC (chat, send with resume, voice), CTCP functions, mIRC colour support with preview, notify list, online help and configurable logging.