There are no globally agreed definitions within web analytics as the industry bodies have been trying to agree definitions that are useful and definitive for some time.
The main bodies who have had input in this area have been Jicwebs (Industry Committee for Web Standards), The WAA (Web Analytics Association) and to a lesser extent the IAB (Interactive Advertising Bureau). This does not prevent the following list from being a useful guide, suffering only slightly from ambiguity. Both the WAA and the ABCe provide more definitive lists for those who are declaring their statistics using the metrics defined by either.

• Hit - A request for a file from the web server. Available only in log analysis. The number of hits received by a website is frequently cited to assert its popularity, but this number is extremely misleading and dramatically over-estimates popularity. A single web-page typically consists of multiple (often dozens) of discrete files, each of which is counted as a hit as the page is downloaded, so the number of hits is really an arbitrary number more reflective of the complexity of individual pages on the website than the website’s actual popularity. The total number of visitors or page views provides a more realistic and accurate assessment of popularity.
• Page View - A request for a file whose type is defined as a page in log analysis. An occurrence of the script being run in page tagging. In log analysis, a single page view may generate multiple hits as all the resources required to view the page (images, .js and .css files) are also requested from the web server.
• Visit / Session - A series of requests from the same uniquely identified client with a set timeout. A visit is expected to contain multiple hits (in log analysis) and page views.
• First Visit / First Session - A visit from a visitor who has not made any previous visits.
• Visitor / Unique Visitor/UniqueUser - The uniquely identified client generating requests on the web server (log analysis) or viewing pages (page tagging) within a defined time period (i.e. day, week or month). A Unique Visitor counts once within the timescale. A visitor can make multiple visits. N.B. The Unique User is now the only mandatory metric for an ABCe audit.
• Repeat Visitor - A visitor that has made at least one previous visit. The period between the last and current visit is called visitor recency and is measured in days.
• New Visitor - A visitor that has not made any previous visits. This definition creates a certain amount of confusion (see common confusions below), and is sometimes substituted with analysis of first visits.
• Impression - An impression is each time an advertisement loads on a users screen. Anytime you see a banner, that is an impression.
• Singletons - The number of visits where only a single page is viewed. While not a useful metric in and of itself the number of singletons is indicative of various forms of “Click Fraud” as well as being used to calculate bounce rate and in some cases to identify automatons (”bots”).
• Bounce Rate - The percentage of visits where the visitor enters and exits at the same page without visiting any other pages on the site in between.
• Funnel analysis Regardless of your visitors’ initial wandering path on your website, they must often pass through a well-defined series of pages in order to convert. It is possible to see the efficiency of each step in this linear process. The funnel narrows as people drop off during each step. High drop-off percentages may signal that a particular step is especially problematic. If problems are uncovered, they may suggest breaking the process up into smaller and more manageable steps, or simplifying it. E-commerce shopping cart abandonment is a common example of this kind of funnel analysis.
• Top exit pages Exit pages are the pages where visitors leave your site. Each exit page can be viewed as a leaky bucket. If visitors exit your site, they probably did not find what they were looking for. In some cases, there is nothing that you can do about this. But for many of the visitors who left, you could have probably improved the page to provide more relevant information or better navigation. The total number of exits and the exit percentage of a page can be used to prioritize among problem pages.
• landing page The first page that a visitor lands on as a result of a traffic acquisition activity. The landing page can be a stand-alone page, a part of a special-purpose microsite, or a page on the company’s main website.
• Click-through rate The percentage of Web page viewers who click on a particular link (also abbreviated CTR). CTR is often applied to the percentage of Internet users who click on a PPC advertisement and land on the advertiser’s landing page.
• Multivariate testing A type of landing page testing methodology where data is collected while simultaneously changing a number of different experimental variables (contrast with A-B split testing
• Deep linking In PPC campaigns,the practice of landing traffic on the most relevant landing page possible within a website.
• Cloaking The practice of showing different content to search engine spiders and human visitors to a Web page for the purposes of manipulating the ranking of the page in search engine results
• A-B split testing The simplest form of landing page testing. A new visitor to the page is randomly shown either the original version (“A”) or an alternative version (“B”).

Popularity: 46% [?]