Behavioral targeting or behavioural targeting is a technique used by online publishers and advertisers to increase the effectiveness of their campaigns.

Behavioral targeting uses information collected on an individual's web-browsing behavior, such as the pages they have visited or the searches they have made, to select which advertisements to display to that individual. Practitioners believe this helps them deliver their online advertisements to the users who are most likely to be influenced by them.

Behavioral marketing can be used on its own or in conjunction with other forms of targeting based on factors like geography, demographics or the surrounding content.

Examples of behavioural targeting in advertising targeting systems include: AdLINK 360, Avail, Boomerang, Criteo, DoubleClick, nugg.ad, prudsys and WunderLoop. These targeting systems allow two main ways of using the technology:

1. They allow advertisers and site owners to display different creative to different people;

2. They allow publishers to sell inventory against specific segments of their audiences to advertisers.

Self-learning onsite behavioral targeting systems will monitor visitor response to site content and learn what is most likely to generate a desired conversion event. Some good content for each behavioral trait or pattern is often established using numerous simultaneous multivariate tests. Onsite behavioural targeting requires relatively high level of traffic before statistical confidence levels can be reached regarding the probability of a particular offer generating a conversion from a user with a set behavioural profile. Some providers have been able to do so by leveraging its large user base, such as Yahoo!. Some providers use a rules based approach, allowing administrators to set the content and offers shown to those with particular traits (wikipedia.com).