Behavioral targeting is, in the context of digital marketing, the practice of using individuals’ web-browsing histories for targeting practices. Interests, projects and life situations are deduced from past online activities.
Visitors’ behaviors can be tracked within a unique website or across a network of websites thanks to cookies.
Behavioral tracking within a unique website is used for audience extension and retargeting campaign. In the latter case, initial behavioral tracking (for instance, a product page viewed without a buy) is done on the ecommerce site, but the targeted visitor is found back on a retargeting network.
Behavioral data collected from a websites network are far more richer. For one individual, hundreds of visits on hundreds of sites can be taken into account and produce a big amount of data.
Different elements can be tracked:
natures of websites and pages viewed
context of pages viewed
tools use (simulator, product configurator, etc.)
search and search clicks
online (and sometimes offline) purchases histories
Behavioral networks establish anonymous profiles of web users who have a score for each interest area. Then, web users are aggregated into target segments offered to advertisers. A target segment can sometimes regroup Internet users who are "in the market" for a product or service (for more details see in-market targeting).
A little showcase of behavioral targeting by IAB UK:
The behavioral targeting network Audience Science offering:
An "in market" segment:
Google Adsense Network uses over two millions partner websites to collect data and to propose very precise interest-based targeting.
Behavioral targeting and advertising raise privacy concerns. Do not track program, cookie opt out initiatives and the IAB Self-Regulatory Program for Online Behavioral Advertising address partially that issue.
The process of collecting data presented by Cisco:
The behavioral targeting process presented by AOL Privacy Gourmet: