Open Source - Internet
http://www.intersectalliance.com/
InterSect Alliance provides software and services relating to audit log/eventlog/event log collection, analysis, reporting, distribution and archive, primarilly through the SNARE series of tools. Snare provides infrastructure that you can use to meet local and federal security requirements such as DCID/DIAM, GBLA, NISPOM Chapter 8, C2/CAPP, Sarbanes Oxley, HIPAA, ACSI 33, Danish Standard DS-484:2005, and California Senate Bill 1386.
http://irssi.org/
Irssi is a terminal based IRC client for UNIX systems. It also supports SILC and ICB protocols via plugins.
http://www.konqueror.org/
Konqueror is an Open Source web browser with HTML 4.01 compliance, supporting Java applets, JavaScript, CSS 1, CSS 2.1, as well as Netscape plugins (for example, Flash or RealVideo plugins).
Konqueror is the file manager for the K Desktop Environment. It supports basic file management on local UNIX filesystems, from simple cut/copy and paste operations to advanced remote and local network file browsing.
http://www.jabber.org/
Jabber is best known as "the Linux of instant messaging" -- an open, secure, ad-free alternative to consumer IM services like AIM, ICQ, MSN, and Yahoo (see the IM quickstart). Under the hood, Jabber is a set of streaming XML protocols and technologies that enable any two entities on the Internet to exchange messages, presence, and other structured information in close to real time.
http://www.phplist.com/
phplist is an open-source newsletter manager. phplist is free to download, install and use, and is easy to integrate with any website. phplist is downloaded more than 10.000 times per month. phplist is sponsored by tincan.