Opt-in is a term related to data privacy. It means a permission given to marketers or data to use the information about the user or perform other marketing activities.
Opt-in is a legal marketing approach when a marketer asks for users’ permission in order to send them promotional content. Opt-in can be full or partial, which means the user can agree to all or just some marketing activities.
Under GDPR , companies are required to ask for consent for sending any advertising messages unless they are processing personal data on the basis of legitimate interest.
Here’s an example of an opt-in placed on the Piwik PRO website – an additional checkbox in a download form:
More about opt-in on Piwik PRO blog: