How DY Considers Multiple Users From the Same Device and Browser

Users with different purchase histories and devices may eventually log into the same browser on a shared device. How exactly does DY review this activity? And how are recommendations influenced by this kind of user behavior? 

Any events, purchases in this case, are attributed to a DYID and to the current CUID in use. If one CUID is logged in and a purchase is made, it is attributed to that CUID.

If a user logs in with another CUID on the same browser and device, the historic purchase isn't attributed again to the new CUID. However, the second user would see the purchase (and other data tied to the DYID) if the site is utilizing an algorithm that relies on historical data, e.g. recently purchased and user affinity.

Using a visual diagram:

User 1 on the moment of Purchase 6 will see recommendations based on Purchases 1, 2, 4 and 5.

User 2 on the moment of Purchase 5 will see recommendations based on Purchases 1, 2 and 3.