Web Log Analysis

From what I've looked at by digging through Wikipedia, web log analysis tools are basically simple web analytics tools. Having used SiteCatalyst in the BYU Web Analytics Competition, sponsored by Omniture, I have a pretty good understanding of what a quality web analytics software package can do.

Web logs work a little differently than the method SiteCatalyst uses to grab it's information. A log file is created directly on the server that hosts the website, and those files contain information about the http request and the machine, browser, etc... that made the request. SiteCatalyst works by embedding some javascript into a page that creates an image with a few pixels of data (I'm pretty sure, I could be way wrong on this) that is sent directly to a server owned and operated by Omniture. To keep the story short, it sounds like web logs work in a very similar way, but there must be some sort of limitation to their use that encourages companies like Omniture and other analytics service providers (ASPs) to grab a little more information than just the basic log.

To be honest, I'm not terribly interested in some of the really technical details of HTTP and web logs, but I find the high level usage of the tools to be relatively interesting.