Please note that that the report abuse button is for serious abuse only. Before you contact customer support, please try to make the distinction between malicious insults and friendly banter.
So please do not report people just for the sake of getting them into trouble- we're not trying to create a police state here!
Certainly we are keen to crack down on those who are spoiling the game for others, but we also want to strike a balance with the idea of freedom of speech.
The upshot of this is that you should only report someone if you feel genuinely offended or upset by what they are saying.
Sensitive souls should note that the Runescape chat filter is already there to stop people from swearing. I think I speak for everyone at Jagex when I say that I hate such crudeness as much as the next massively multi-player online roleplaying game; but if a word has already been censored, you don't need to report it.
By the same token, it is a waste of time getting into 'tit for tat' abuse reports. We try not to get involved in petty squables, and we have no plans to introduce a Report Abuse abuse button...