AWStats

AWStats is a free powerful and featureful tool that generates advanced web, streaming, ftp or mail server statistics, graphically. This log analyzer works as a CGI or from command line and shows you all possible information your log contains, in few graphical web pages. It uses a partial information file to be able to process large log files, often and quickly. It can analyze log files from all major server tools like Apache log files (NCSA combined/XLF/ELF log format or common/CLF log format), WebStar, IIS (W3C log format) and a lot of other web, proxy, wap, streaming servers, mail servers and some ftp servers.
Take a look at this comparison table for an idea on features and differences between most famous statistics tools (AWStats, Analog, Webalizer,...).
AWStats is a free software distributed under the GNU General Public License. You can have a look at this license chart to know what you can/can't do.
As AWStats works from the command line but also as a CGI, it can work with all web hosting providers which allow Perl, CGI and log access.

• Number of visits, and number of unique visitors,
• Visits duration and last visits,
• Authenticated users, and last authenticated visits,
• Days of week and rush hours (pages, hits, KB for each hour and day of week),
• Domains/countries of hosts visitors (pages, hits, KB, 269 domains/countries detected, GeoIp detection),
• Hosts list, last visits and unresolved IP addresses list,
• Most viewed, entry and exit pages,
• Files type,
• Web compression statistics (for mod_gzip or mod_deflate),
• OS used (pages, hits, KB for each OS, 35 OS detected),
• Browsers used (pages, hits, KB for each browser, each version (Web, Wap, Media browsers: 97 browsers, more than 450 if using browsers_phone.pm library file),