When an unidentified visitor enters a site that contains the Dynamic Yield script they are given a unique DYID. The DYID is stored in the cookies, session storage, and local storage of the browser. This allows us to track and target the user based on their behavior and metadata as long as they are using the same browser on the same device and do not delete the cookies and cache.
However, there are two additional levels of information about users you can provide Dynamic Yield which will enable richer targeting options and experiences.
In order for Dynamic Yield to target the same visitor across different channels (Desktop, Mobile, Email) the visitor must be identified on each of the distinct platforms with the same Customer Unique Identifier (CUID). Users are identified when an event or API is sent to Dynamic Yield with a CUID, but you can also identify site visitors that have been invited to your site via an email campaign.
Dynamic Yield does not store any personally identifiable information (PII) about our users. So, for example, when we receive an email that identifies a particular user, we hash the email before storing it to protect user privacy. This means that Dynamic Yield will not be able to use the email or identify the users externally without additional steps.
In order to enable triggered emails and audience export, identified users must be matched to an email address or other identifier. This is accomplished by uploading a data feed of type User Email. The feed consists of one column of identifiers. Dynamic Yield then hashes these identifies and checks for matches among identified users. When a match is found, these users are called matched users, and are eligible to be included in triggered emails and audience exports. The unhashed emails are stored separately from our other data in a highly secured location.