There is now a variety of tracking website applications for various CMS, blogs, forums and website platforms for you to choose from, and many more are in development. If you are serious about tracking your website's return on marketing investment, or simply want to know where your visitors are coming from, here are a few lists that could help you monitor and analyze your web traffic.

Google Analytics - Google’s free analytics software. Unlike some enterprise apps, the stats are usually on a delay of a few hours.
Google Analytics
VisiStat - Real-time tracking with graphical and intuitive reporting features.
VisiStat
ShinyStat - Web analytics with three available packages that range from a free package that is basically a souped-up hit counter to a full-featured business edition with conversion and campaign tracking.
ShinyStat
Pagealizer - Web analytics that actually suggest changes and optimizations for your pages.
Pagealizer
Woopra - Analytics suite that includes click-to-chat functionality and real-time notifications.
Woopra
JAWStats - A free, open-source analytics package that displays your stats using charts, graphs, and tables.
JAWStats
clickdensity - Heat maps with real-time visitor data to help you optimize your link and ad placement and enhance your site’s stickiness.
clickdensity
WASP - Web Analytics Solution Profiler is a Firefox extension that helps you understand how your web analytics solution is being implemented.
WASP
popuri.us - A tool to check your ranking and popularity on a variety of sites including Alexa, Google PageRank and more.
popuri.us