What is unknown user in Kakaotalk

Today one of my foreign reader asks me about some of extraordinary thing on the Kakaotalk messaging service.

Actually she wonders why there is "unknown" user in her Kakaotalk chatting room even it was her friend's name just before.

I have also see this kind of thing in my Kakaotalk. Therefore I want to verify when this is happened.

Another question is about adding the friend. She actually experienced that her friend was automatically added to her Kakaotalk friend list without any request.

Why and when is this kind of thing happened ? What do we do upon this case ?

Unknown user in Kakaotalk, Source: Office clip art

The whole question from foreign reader is as follows. I will cover her question through the test in below.

Question from foreign reader.

Hi

I am using kakaotalk and today this morning when I checked my contact lists in kakaotalk, one of my friends whom I used to talk to sometimes disappeared from my contact list, and then when i looked in the chat message history i had with him his name showed up as unknown without his actual name in kakaotalk, then there was like a grey highlighted portion on that message chat history, then its so weird after like an hour he appeared again my contact list, what does this mean? does this mean he blocked or deleted me in kakaotalk? hope you can help me figure out the answer to my question. thanks

2nd question:

I was thinking there should be another friend request if he was gonna add me back, but all i received was his name again as a contact in my kakaotalk wihout any friend request from him, and i want to know how do you know if someone blocked or deleted you in kakaotalk?

"Unregister" from Kakaotalk makes him/her "Unknown user" in Kakaotalk.

I set up one test Kakaotalk account named "SenseChef" and chatted as shown in below. Everything is normal like other accounts.

Next screen is just inside of chatting room. "SenseChef" name is just shown up well.

Now I unregistered "SenseChef" acccount. Then chatting room was changed as below. Unregistered "SenseChef" now become "Unknown".

"SenseChef" account's profile is also changed to "Unknown".

Therefore we can say that "Unknown" user means he/she just unregistered from Kakaotalk. This is not happened when I block somebody. "Unknown" user is coming only from unregistration on Kakaotalk.

Added friend without any request is just what Kakaotalk has been designed.

What happen if unregistered friend is creating his/her Kakaotalk account again ? All of his/her friends having their phone number stored in smartphone will be automatically added without any friend request. The friend request is only shown up under having no telephone number for somebody.

In above questioned case, I guess her friend might unregistered and recreated Kakaotalk account by some reason.

Unregistration might impact to delete all information on Kakaotalk and to be shown up something extraordinary to their friends. Therefore unregistration should be done in only very limited, unavoidable case.