Behaviorally-targeted advertising (also referred to as online behavioral advertising [OBA] or interest-based advertising) has been defined by the Digital Advertising Alliance (DAA) as "the collection of data online from a particular computer or device regarding Web viewing behaviors over time and across non-affiliate Web sites for the purpose of using such data to predict user preferences or interests to deliver advertising to that computer or device based on preferences or interests known or inferred from the data collected."
The definition has largely been accepted by the Federal Trade Commission, and is described in similar fashion in its Self-Regulatory Principles for Online Behavioral Advertising. This type of advertising is precluded by the Children’s Online Privacy Protection Act (COPPA) for children under 13 without prior, verifiable parental consent, as well as by the existing self-regulatory advertising groups, including DAA and the Network Advertising Initiative (NAI). Please see our Student Data Protection Addendum for additional information regarding our commitments on targeted advertising.
Contextual targeting (also referred to as contextually relevant advertising) is defined by DAA as advertisements that are delivered “based on the content of a Web page, a search query, or a user’s contemporaneous behavior on the Web site.” NAI expands a bit further explaining, “the ad selected depends upon the content of the page on which it is served, or ‘first party’ marketing in which ads are customized or products are suggested based on the content of the page or users’ activity on the page (including the content they view or the searches they perform).”
The FTC echoes this in policy statements and in comments surrounding COPPA. There, the FTC notes that contextual targeting, “is more transparent and presents fewer privacy concerns as compared to the aggregation and use of data across sites and over time for marketing purposes.” Contextual targeting is permitted under COPPA.
Also see the California Attorney General's guidance on SOPIPA:
https://oag.ca.gov/sites/all/files/agweb/pdfs/cybersecurity/ready-for-school-1116.pdf