What is the logic behind delete other-end chat?

Question

I am design a social network site. One of the most important feature of site is chatting.

But I have no idea that should I give feature to delete messages including other end too. (Eg: If A send a message to B, should I allow A to delete just his own message or even with B message).

Let say two sample popular apps.

1. WhatsApp : When you send a message, you can delete message even the other-end...

2. Facebook : You can delete only your own message. Even you delete message, still other end can read it.

Above both companies handled by same company. But they use two different way.

What is the logic behind it?

Answer 1

You should consider the ramifications behind allowing someone to delete a message in context and base your decision on that.

If you allow someone to delete a message and don’t provide all possible observers of the message log a way of knowing that the message log was altered, you are opening the log up to abuse.

User A could bait User B into posting certain messages in a sequence. User A then deletes their messages and User B’s dialog could mean something very different.

Consider this contrived example:

Original Chat

A: Hello B, did you mow the lawn today? 
A: also, can you take out the trash? (Possibly while B is typing) 
B: Yes 
B: No

After A Deletes

A: Hello B, did you mow the lawn today?
B: Yes 
B: No

It can look like B is saying, “No, I didn’t mow the lawn”. Even though User A changed the messages.

I think that, whether you implement deletion or not, you should provide a visual cue in the chat log that a message was deleted.

Consider the alternate:

Original Chat

A: Hello B, did you mow the lawn today? 
A: also, can you take out the trash? (Possibly while B is typing) 
B: Yes 
B: No

After A Deletes

A: Hello B, did you mow the lawn today?
A: -message deleted by user-
B: Yes 
B: No

Now outside observers at least know to question what the deleted message was.

Answer 2

The logic of deletion the other-end chat message is to allow a user to control the history of a conversation, and remove undesired parts of it if necessary.

From UX perspective there is no right answer whether allowing message deletion or not, it depends on the intention of a messenger as a tool.

A presence of such facility affects the way users may want to communicate, and Facebook might want to attract as many people as possible to its services, building applications with different abilities.

Answer 3

Type 1 (WhatsApp) where anyone can delete any message is used in contexts of security and privacy, wherein anyone in the message chain may have reason to delete all messages at a moment's notice. Underworld examples would be sex workers (escorts) and their clients, or drug dealers, those on the TOR network... or on a more positive note, political activists especially in nations like China or Iran probably need such a messaging system due to the implications of speech in those nations.

Or let's say Dick and Jane are having an affair, and sending nude selfies to each other. They probably want to be able to delete the entire threads to prevent their spouses from finding them.

Using your imagination, you could certainly find many more uses where privacy is critical. Of course, if the app is saving anything to the flash drive, well that can be recovered unless somehow encrypted.

Type 1 is thus "halfway" between a snapchat-type model where all messages vanish after reading, and the more common Type 2 (Facebook) model, where any recipient can keep all their messages, as they have received them.

Answer 4

The purpose to delete the other-end chat is for privacy and security.

Take for example Person A wants to forward their account details to Person B for whatever reason.

(They've copied the account details from a note app where it is stored.)

Person B's perspective

Person A: Here's my account details:
          Username: Mary LostBoat
          Password: MaryL1986
          Email: [email protected]

Few seconds later, Person A realized that they have accidentally gave out their password, and decides to delete the other-end chat.

Person B's perspective

Person A: *Message deleted*
Person A: Oops, I've accidentally sent my password...
Person A: Here's my account details:
          Username: Mary LostBoat
          Email: [email protected]
Person B: Ok

Person B doesn't know Person A's account password. This isn't the best example, but you get the idea.

Answer 5

WhatsApp - Its mainly one to one or Closed group conversations. One can not go to your whatsApp account and see what you discuss/share in other groups like people do in Facebook.

Facebook - Its truly "Social" networking. Like a social gathering (party), where whatever you discuss in a group will be stored (remembered) by people in a group AND also by people passing by your group (your friends). I am not sure if I am able to give correct metaphor for Facebook conversation to that of Party scene.

Now, IMHO, when we say "Social", whatever we talk is bound to be remembered by whoever has interest in that topic. Private conversations should be done in private, not on social n/w site. Like they say, best way to keep a secret is not to tell that to anyone.

So, coming back to your question - "Should I give feature to delete messages including other end too?". My opinion is -

Deleting message from your own inbox is "User's" decision for whatever reason and "User" would be responsible for the confusion/misunderstandings while reading that chat later.

It's ok to delete message from other's inbox, if it is one-to-one communication, where you can say, "I am sorry I did not mean it, or I sent it by mistake". Otherwise in a group chat, deleting certain messages from a chain of may (will) create misunderstandings.

Please explore "why" someone might want to delete a message? If by mistake he types in something, or sends message in wrong window, them make UI such that users wont commit such mistakes. May be showing group name promptly, color coding groups based on genre/social setup, alert with smart confirmations (avoiding abusive language in family groups) etc.

I would like to repeat - social networking is not for private messages. It's like shouting in public. See if by design can we minimize instances where user has to recall/delete what he has posted. If user is sure while sending something and regrets later...well..you can't rewind in social conversations. This makes social networking site truly social and not where you say something and back off later.

One more point, instead of deleting posts from other's inbox, you can have facility to mark it "non-relevant". This way, people will understand you don't stand by your earlier thoughts anymore (this is accepted as new learning can alter our beliefs). But deleting will surely cause confusion/misunderstandings.