talking to unknown users in fb/messenger

[zoran]

When i talk to someone i don't know/not friends with in fb/messenger, can he talk back to me or do i have to add him?
And if i add him, can he see my photos like he is a friend?

 

[0007776]

They can, I believe by default the first message you send is hidden away somewhere that they have to be looking to see it though.

 

[zoran]

Why is there an "add to messenger" option? If that is checked do they become friends and can see my profile like friends do?