Does ECID/MID/VisitorId change every time user deletes cookies ?

[Shaista_L]

Hi All,

We have recently implemented ECID, The reason for implementation was to uniquely identify customers. Can anyone please answer the below questions.

1. Does the value of ECID/MID/Visitor Id which is a long string of numbers  (17050896330536188461601914392312074335) changes every time the user deletes cookies  ?

2. Let's assume it does change, is there a way to identify the user as returning visitor and assign back the same value?

    We have our own customerId that we assign to an evar , The problem here is due to unknown reasons we are unable to identify our customer when they login, the          evar value is not always populated, I am trying to figure out a way to tie back the customer Id to the ECID value always, irrespective of if the customer deletes       cookies or not .

3. Does the value of mcvisid_high and mcvisid_low change too when cookies are deleted ?

4. Can two users have the same ECID value ?

5. Another issue, we want to overcome is when multiple users use the same device , the ECID value remains same. Is there an identifier that uniquely distinguishes between users, I have checked the user_agent value , it is also same.

6. Where can I find the demdex cookie value ? Is it always present ? Does the DEMDEX cookie value also changes when a user deletes cookies ?

Thanks in Advance.

ankits28281247

  sanmeetw15198549

Andrey Osadchuk

[Ankit_Sharma_]

Here are my answers to the questions

1. Does the value of ECID/MID/Visitor Id which is a long string of numbers  (17050896330536188461601914392312074335) changes every time the user deletes cookies  ?

Yes, if DEMDEX which holds (AMCV/AMCVS) cookies deleted from the browser

2. Let's assume it does change, is there a way to identify the user as returning visitor and assign back the same value?

    We have our own customerId that we assign to an evar , The problem here is due to unknown reasons we are unable to identify our customer when they login, the          evar value is not always populated, I am trying to figure out a way to tie back the customer Id to the ECID value always, irrespective of if the customer deletes       cookies or not .

I don't think there is a good way to do, however using customer attribute you can upload the customerID's which can be tied to multiple mid's tie to the same customerID value but that won;t help in getting the returning visitors information as returning visitor are based of cookies (mid/s_vi) values

3. Does the value of mcvisid_high and mcvisid_low change too when cookies are deleted ?

yes when demdex cookie is deleted as it's stored in demdex

4. Can two users have the same ECID value ?

No

5. Another issue, we want to overcome is when multiple users use the same device , the ECID value remains same. Is there an identifier that uniquely distinguishes between users, I have checked the user_agent value , it is also same.

I don;t think there is a good way to do that, until you have a way to authenticate the users, once that's done you can leverage the customer attribute.

6. Where can I find the demdex cookie value ? Is it always present ? Does the DEMDEX cookie value also changes when a user deletes cookies ?

you should see that in network call, it set first hit of the visitors, Yes Demdex also changes if users deletes that.