Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache SpamAssassin to be used in a wide variety of email systems.
weta-dfs is a distributed file system. It is designed to be fail-safe through replications of files, fast and easy to install, platform independent, and to have fast recovery from crashes. It consists of Data Node Servers and one Meta Data Server and a java.io.File-like client API.
The Privilege Separation patches for Apache HTTPD and 'mod_dav' address the problem that an Apache WebDAV server can only write files as the non-privileged Web server user (usually something like 'nobody' or 'www'). The patches address this shortcoming in a secure way by adding privilege separation to the Apache Web server (conceptually similar to SSH privilege separation). A privilege-separated Apache can be used to provide secure WebDAV write access to ~user directories and allow the use of per-user Unix quotas. When combined with mod_ssl, it provides a convenient and secure remote file serving system, as WebDAV clients are seamlessly integrated into both Windows and Mac OS X.
Cosmo is the OSAF calendar sharing server. With your favorite calendar program (Chandler, Apple iCal, Mozilla Sunbird, or any other WebDAV or CalDAV enabled client), you can share your calendar with other people by publishing it to Cosmo. Your shared calendars can be subscribed to and updated by anyone, even if they don't have an account on your server. Cosmo provides Atom feeds for shared calendars, so you can track updates in your favorite feed reader and integrate your calendar into your Web site or blog.
Echomine Feridian is an easy-to-use Java API that gives you quick and easy access to the XMPP network used in IM services such as Google Talk. The API allows you to communicate with Jabber/XMPP servers for sending and receiving instant messages, presence management, and custom extensions to the XMPP protocol.
SubEthaSMTP is an easy to understand Java library that provides a receptive SMTP server component. By plugging this component into your Java application, you can easily receive SMTP mail using a simple abstract Java interface. Also included is a small sub-project called Wiser, an easy to use incoming mail testing framework.