There are counters (external programs) and log analyzers (internal programs) for collecting statistics on web resources attendance.
Website viewing counters: Google Analytics, LiveInternet, 24Log, RAMBLER top100, HotLog, Rating@mail.ru, InetLog, WarLog, Openstat, Hit Counter.
Log analyzers are local internal programs installed on a user’s computer, which collect server logs (log files) accumulated by the server (which hosts the site). The program processes this data and stores them in the form of statistics. Detailed site statistics is a quality tool for improving the site. So, with its help, you can answer the questions, how many unique visitors to your Internet resource, from where visitors come to you, on what requests, how many and which pages each user viewed, from which page the user left the site, how often users again return to your site, etc. This will help to control and regulate the work of the site, seeking from it the maximum benefit and impact.