Total same

KEEP in touch (with someone or something), REMAIN in touch (with someone or something) and STAY in touch (with someone or something) are all the same. All mean to maintain communications with someone; to maintain up-to-date knowledge about someone or something look at these sentences: - After my neighbor moved, we still remained in touch. - I want to stay in touch with my office over the someone or something, even during weekends. Some times Keep in touch means: Good-bye. (Sometimes a sarcastic way of saying good-bye to someone one doesn't care about.) - Nice talking to you. Keep in touch. - Sorry, we can't use you anymore. Keep in touch. note: for me STAY in touch is a bit more formal; If somebody told me "stay in touch" I'd feel a lot more obliged to do so since it would seem like they actually cared. ;) Good Luck