Web analytics is a phrase used to describe the collection and analysis of traffic to and from an online site. There are two distinct sides of web site analytics; on-site web analytics and off-site web analytics.

On-site web analytics refers to the analysis of Internet traffic to a web site and what a visitor does once they are at the site. This can include information on unique visitors, repeat visitors, page views, average time between repeat visits, geographical location of visitors, what browser a visitor uses and a slew of other information.

Off-site web analytics is a more generalized analysis of the overall potential and presence of a web site on the Internet. This includes what the potential audience for a web site might be, how well-ranked and visible that site is and how the site's online reputation is perceived.

In general, web analytics most often refers to the category of on-site analysis. Tools built to evaluate this information, such as Google Analytics, provide web site managers and owners with the ability to access a wide range of important data on visitors to the site. This information can then be used to evaluate advertising and marketing strategies, the results of social media marketing or even the base usability of the site's design.

To prime a site for effective web site analytics, the site is generally 'tagged' with coding that provides information on the site's visitors to a web analytics service. These services, such as Google Analytics, then process and compile the information to be easily accessed by the web site owner or manager. For example, a Google Analytics user can quickly see what pages on a site are most popular, where the majority of a site's web traffic is coming from or what keywords visitors are primarily using to find the site on Google Search.

Some web analytics services use a different method of data collection called logfile analysis. This records information collected when a web server automatically creates logfiles about visitors to the web site. This method of retrieving web site analytics does not require the effort of coding the pages of the site to process the information. However, this method does not record information about activity on cached pages, which can account for a significant amount of page views on a site. Thus, logfile analysis is not highly regarded for web traffic analysis of site visitors.

Managing a successful advertising campaign or properly revising a site for search engine optimization relies on having detailed and accurate web site analytics information. For example, knowing the keywords or phrases that people have used most frequently to find and visit your site on Google Search might prompt a pay per click advertising campaign through Google AdWords to increase that specific web traffic even more. Discovering that content about a certain topic brings a large amount of visitors to a site could mean even more traffic if additional similar content is published. Website analytics can also show you where advertisements on web sites or in search engines are not bringing in valuable traffic and can be cut to save money for more successful marketing efforts.

Many free web analytics tools, such as Google Analytics, can be found online and provide a great deal of vital information about a web site's traffic and the behavior of its visitors. For even more detailed web analytics and analysis, there are also website analytics software options available and paid online web analytics services. No matter what source of information is used to collect this information, the data is extremely valuable to run any successful web site.