Definitions

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.

Click path: The sequence of hyperlinks one or more website visitors follows on a given site.

Click Through: Number of times a link was clicked by a visitor typically associated with advertising activities.

Conversion: A visitor completing a target action.

Cookie: Small piece of text stored on a user's computer by a web browser. A cookie consists of one or more name-value pairs containing bits of information that store information like the frequency a website is visited. This information can be recovered on the server on the following visits.

CPA: Cost-Per-Action. Online advertising payment model in which payment is based solely on qualifying actions such as sales or registrations.

CPC: Cost-Per-Click. The cost or cost-equivalent paid per click-through.

CPM: Cost-Per-Thousand impressions. Many online ads are priced on a CPM basis in which the cost is expressed for 1000 impressions. E.g. If a banner advertisement is placed at the price of $20/M then the CPM is $20, or $20 for 1000 impressions.)

Duration 

• Active Time / Engagement Time: Average amount of time that visitors spend actually interacting with content on a web page, based on mouse moves, clicks, hovers and scrolls. Unlike Session Duration and Page View Duration / Time on Page, this metric can accurately measure the length of engagement in the final page view.
• Frequency / Session per Unique: Frequency measures how often visitors come to a website. It is calculated by dividing the total number of sessions (or visits) by the total number of unique visitors. Sometimes it is used to measure the loyalty of your audience.
• Page Depth / Page Views per Session: Page Depth is the average number of page views a visitor consumes before ending their session. It is calculated by dividing total number of page views by total number of sessions and is also called Page Views per Session or PV/Session.
• Page View Duration / Time on Page: Average amount of time that visitors spend on each page of the site. As with Session Duration, this metric is complicated by the fact that analytics programs can not measure the length of the final page view unless they record a page close event, such as onUnload().
• Session duration: The length of time in a session. Calculation is typically the timestamp of the last activity in the session minus the timestamp of the first activity of the session. When there is only one piece of activity in a session, no visit duration is typically reported; this is because analytics programs can not measure the length of the final page view unless they record a page close event, such as onUnload().

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.

Impression: A single instance of an online advertisement being displayed. Everytime a banner or ad appears.

Landing page: A page intended to identify the beginning of the user experience resulting from a defined marketing effort.

Metrics

• Count: The most basic unit of measure; a single number, not a ratio. Often a whole number (Visits = 12.398), but not necessarily (Total Sales = 5.542.232€)
• Ratio: Typically, a count divided by a count, although a ratio can use either a count or a ratio in the numerator or denominator. (An example of a ratio fabricated from ratios is “Stickiness.”) Usually, it is not a whole number. Because it’s a ratio, “per” is typically in the name, such as “Page Views per Visit.” A ratio’s definition defines the ratio itself, as well as any underlying metrics.
• KPI: Key Performance Indicator. While a KPI can be either a count or a ratio, it is frequently a ratio. While basic counts and ratios can be used by all Web site types, a KPI is infused with business strategy —hence the term, “Key” — and therefore the set of appropriate KPIs typically differs between site and process types.

Page view: The number of times a page (an analyst-definable unit of content) was viewed. Web server responses returning status codes indicating the requested content was missing (400 to 499) or there was a server error (500 to 599) should not be counted as a page view unless the web server has been configured to return a real page in the same response with the status code. Web server responses returning status codes indicating redirection to another page (300 to 399) are also not typically counted as page views.

PPC: Pay-Per-Click (PPC) refers to a class of internet advertising in which advertisers pay a fee for every visitor that clicks on their ad. PPC is often used to refer to keyword advertising on search engines and other websites.

Referrer: The referrer is the page URL that originally generated the request for the current page view or object.

SEM: Search Engine Marketing. Form of Internet marketing that seeks to promote websites by increasing their visibility in search engine result pages (SERPs) through the use of paid placement, contextual advertising, and paid inclusion.

SEO: Search Engine Optimization. Process of improving the volume or quality of traffic to a web site from search engines via "natural" or un-paid ("organic" or "algorithmic") search results as opposed to search engine marketing (SEM) which deals with paid inclusion. Typically, the earlier (or higher) a site appears in the search results list, the more visitors it will receive from the search engine.

Singletons: The number of visits where only a single page is viewed. 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.

SMO: Social Media Optimization. Set of methods for attracting visitors to website content by promoting and publicizing it through social media.

Unique User / unique visitor: The number of inferred individual people (filtered for spiders and robots), within a designated reporting timeframe, with activity consisting of one or more visits to a site. Each individual is counted only once in the unique visitor measure for the reporting period. The identification is done through the device used to access the website, usually cookies or IP address + User Agent combination., so the same person visiting throught different browsers will be counted as 2 different unique users.

Visit / session: A visit is an interaction, by an individual, with a web site consisting of one or more requests for an analyst-definable unit of content (i.e. “page view”). If an individual has not taken another action (typically additional page views) on the site within a specified time period, the visit session will terminate.