ModLogAn is a modular logfile analyzer that combines speed with flexibility. It parses the logfiles generated by several server-types (HTTP, FTP, mail, streaming, etc.) and other logfile sources (flow-tools, ipchains, PABXs): currently 24 parsers. It features incremental logfile processing and internal resolving, and is able the split (mass-hosting) and combine logfiles (clusters) internally. The output can be based on the internal template engine to generate your own look & feel.
NewSyslog is an updated version of a package put together by Theodore Tso of MIT Project Athena (which is included in NetBSD, FreeBSD, OpenBSD, etc.). It manages the rotation and archiving of log files (primarily those written to by syslogd). This version has a mix of features from all of the other versions, and it has been made more portable than any of the others with the help of GNU Autoconf.
Onis is a script that converts IRC logfiles into an HTML statistics page. It provides information about daily channel usage, user activity, and channel trivia. It provides a configurable customization and supports Dancer, dircproxy, eggdrop, irssi, mIRC, and XChat logs. Persistent data (history files) and automatic log purging make onis applicable for a large number of logfiles. It also features a powerful translation infrastructure.
pflogsumm.pl is designed to provide an over-view of postfix activity, with just enough detail to give the administrator a "heads up" for potential trouble spots. Reports includes: Total number of messages and bytes; Hosts/Domains; senders and Recipients; per-hour traffic reports; summaries of warnings, fatal errors, and panics; and so on ...
phpOpenTracker is a framework solution for the analysis of Web site traffic and visitor behaviour. It features a logging engine that, either invoked as a Web bug by an HTML image tag or embedded with two lines of code into your PHP application, logs each request to a Web site into a database. One installation can track an arbitrary number of Web sites. Through its API, you can easily access the gathered data and perform complex operations on it (for instance, the analysis of your visitors' click paths).