a kin is a character (or characters, you can have more than one kin) you associate/identify with. kins are to help you express yourself, comfort you etc.
The Kin phone became dead to Microsoft thus coining the slang term 'kin' as a verb. Similar to other technological words on the forefront of language being used as verbs i.e. google and bing
Can be used in place of kill in almost any situation.
the word "kin" is used when you and a character share a simularity, it's usually used for anime characters (and lets keep itthat way ._.) but you can use it for other characters outside of anime.