This one was my personal favorite for a long time, however their server lag had got pretty bad at one point so I had to remove it as my default tracker. My opinion though is give it a try since you may not have the same problem and in my opinion it is one of the best trackers out there. There's a ton of information and it's stats are live (yup, you get truly up-to-the-second info!). W3Counter's key features are the detailed info about referrers, private stats, visitors display settings, browsers, platform, and that I can easily tell which pages people bounce out of too fast. (ie. arrive then hit the back button.) It also offers stats for your blog feeds and podcasts!
I think though the feature that stands out most for me is the "site overlay" that shows what links on your pages are clicked the most. With this feature you can go through your entire site looking at internal traffic patterns! At the moment it will only track internal links, not outbound traffic.. but my fingers are crossed that will be in the next version that's currently being worked on. For the free account you can only track one website, and a tiny button is shown on your page... very worth it.
I ran this on Webweaver for a quite a while now and am fairly impressed with some of the information, other areas are less impressive than I'd hoped. I'll start with the good points... It gives very detailed information about ROI (Return On Investment), and goal tracking, conversion etc. so if you advertise using Adwords or other PPC, CPA etc. ads that will be a great help. So if you do want that info.. this may be the best free service for you. Honestly, I can't tell you if those statistics are really useful or not, since all my traffic is organic and I'm not selling anything I can't test it.
Another good point is that their server has very few slowdowns, so not a lot of lagging and slowing the load time of your site. Also their Navigational Analysis and Web Design Parameters sections do give detailed information that I've seen on few other tracking services.
They also can give you quite a bit of information about what your visitors are looking for (and whether they find it) on any internal site search you may have.
The bad points... If you are wanting to see the entire URL for your referrers, including anything past a query string... you'll be disappointed. That information is not available in Google Analytics. The best you get is having to copy and paste pieces into your browsers address bar (the domain, then the rest of the url, minus the missing query string info). For me not being able to see exactly where my traffic is coming from is a show stopper, if you get a lot of traffic from forum posts, blogs and search engines.. you may not get all the statistics you want with this.
All in all it's a good service, and I do use it quite often in combination with a different tracker that will give me a bit more detailed referrer info. Depending what your tracking goals are for your website this might be a good solution for you as well.
Stat Counter Great statistics and an invisible tracker is available. I tested this one on Webweaver and am pretty impressed with the amount of visitor information they provide. Key features for me were the referrer information that includes somewhat detailed keyword analysis, the fact that at a glance I could see which pages are most popular and just for curiosity which countries my visitors are from. Their free statistics tracker does have log size limitations, so for large sites this may not provide enough information. Worth trying though, even a glimpse of real time stats is handy at times!
Very thorough statistics that can also tells you exit / Adsense link clicks without needing to add extra code to any of your outbound links. I haven't tested this one as thoroughly lately but it has changed a lot since my last review, and for the better. It gives a ton of information about your visitors including where they came from, navigation paths, system information (browsers, operating systems, javascript etc.) and quite a bit else. I have to admit, the stats pages do look nice as well. The only drawbacks for me are that the tracking button is a bit large (invisible tracker is available as a paid upgrade) and that navigating the information they give is (for me) a bit unintuitive.
The counter has many different styles and colors to choose from and each member ID can have 3 counters. They offer hourly statistics with graph, daily statistics, monthly statistics and statistics for the whole year. The info is rather basic, but for many personal websites it's easier than getting bogged down with stuff you don't care about anyway. You can change the look of your counter anytime without losing visitor information and change the value of your counter at anytime. They offer tons of other free resources for your website here as well!
This is another free website tracking service I've used here. They offer among the more detailed stats in a free service. I haven't tested them in quite a while, so I can't give a current review.
SiteGagdets provides a free download tracker that tracks the number of times each of your files are downloaded. Find out which files are most popular, and which are not. They also offer the standard website counter to keep a basic tally of total visitors.