The definition of an institution is an established custom or practice, or a group of people that was formed for a specific reason or a building that houses the group of people. Marriage is an example of a cultural institution.
Contextual targeting is a type of targeting on the Google Display Network in which you select specific keywords or topics and then allow AdWords to identify websites that are a good fit for your keywords and targets.
In this article, Jose Carlos Cortizo explains what Behavioural Targeting is and introduces how it can be used within E-commerce sites. Many of these approaches can and should be used for other types of business, so you may want to serve different content or offers to returning visitors for example.