If you unsubscribe from a friend on facebook then resubscribe, will they know?

[jny]

I think if you unsubscribe a friend, they do not get a notification so they won't know. But if you subscribe to their updates again later on, will they get some sort of notification telling them that?

Also, if you delete a friend from facebook, will all the previous wall posts you put on their wall disappear too?

[Peter]

Yes all wall post will no be shown unless u have ur page for public u have to put it private also they wouldn't get a notification in terms to their updates

[benjaminio]

They will get a notification if you add them, not if you delete. The wall posts don't disappear. You can temporarily block someone, you add them to your block list under privacy settings.