The opportunities afforded by the Internet greatly overshadow the challenges. While not forgetting this, we can nevertheless still address some of the problems that arise. Hate speech online is one such problem. But what exactly is hate speech online, and how can we deal with it effectively? As with freedom of expression, on- or offline, UNESCO defends the position that the free flow of information should always be the norm. Counter-speech is generally preferable to suppression of speech. And any response that limits speech needs to be very carefully weighed to ensure that this remains wholly exceptional, and that legitimate robust debate is not curtailed. A typology of responses is elaborated in this study.