Although antiquated, to 'put the kettle on' is to say that the conversation will continue because of some new deep or entertaining news has been revealed and needs discussing, usually this involves actually making a new cup of tea (giving time to savour the space before gossip) but...

'Kettle on!' has no intention of actually making tea and can be said anywhere, it's like saying 'oh fuck me, this is news' or 'you have my undivided attention', 'I need to know everything'

Internet persona(s) who happens to follow you and you happen to follow them back and maintain communication with and have a mutual liking for eachother whether it be friendship wise, etc. (Mutuals if more than one mutual)