The internet brings out the ugly side of human behaviour.
Why else would it seem to some that to threaten a person with rape, order them to die or harass them with obscene and menacing messages is acceptable?
Lurking behind their computer screens, these cowardly internet trolls probably wouldn't say boo to the target of their venom if they met them on the street.
But give them a Twitter account and they'll call Rory McIlroy a "Brit w*****" and tell him to "f*** off".
Trolling is a trend that has been replicated the world over against high-profile figures.
Richard Madeley's daughter Chloe was this week threatened with rape by trolls and X Factor contestant Stephanie Nala was told to "die".
Gerry and Kate McCann, who are still struggling to come to terms with the disappearance of their daughter Madeleine, have been subjected to online threats of violence and kidnapping.
Zelda Williams, the daughter of the tragic US actor Robin Williams, recently quit Twitter after internet trolls posted fake photographs claiming to be her dead father.
There are some astute online bullies who take measures to hide their identities. But the majority of these trolls are complete idiots.
As soon as someone Googles their name, their unpleasant, nasty and even sinister comments are there for the whole world to read.
It's not very good for job prospects if an employer decides to carry out a quick background check online.
For Rory McIlroy, it won't be the last time trolls target him.
But as the second richest Irish sports star – with an estimated fortune of £28m, according to the Sunday Times Rich List – enjoying the golden days of his career, the golf ace will always have the last laugh.